ENHANCED TYPE II CALLER ID DECODER
WITH STUTTER DIAL TONE DETECTOR

NW6006

The IDT logo is a registered trademark of Integrated Device Technology, Inc

INDUSTRIAL TEMPERATURE RANGE

JULY 2002

2002 Integrated Device Technology, Inc.

DSC-6049/3

FEATURES

1200 baud Bell 202 and ITU-T V.23 Frequency Shift Keying
(FSK) Demodulation

Stutter dial tone detection

Compliant with following specifications:
Bellcore GR-30-CORE & SR-TSV-002476
TIA/EIA-716, TIA/EIA-777 Draft
TIA/EIA PN-4195 Draft
British Telecom (BT) SIN227 & SIN242
ETSI ETS 300 778-1 and -2

Bellcore "CPE Alerting Signal (CAS)", British Telecom "Idle State
and Loop State Tone Alert Signal" and ETSI "Dual Tone Alerting
Signal (DT-AS)" detection

Two seperate OP amps with adjustable gain for Tip/Ring and
Telephone Hybrid connections

Monitoring of the stop bit for framing error check

Serial FSK data interface with selectable output of bit stream or 1
byte buffer

FSK carrier detection

3 V or 5 V operation

Low power CMOS with intelligent powerdown mode

Operating temperature range: -40 °C to +85 °C

Packages available:
NW6006-XS 20 pin SOIC

(where `X' is the revision ID)

DESCRIPTION

The NW6006 device is a single-chip, 3/5 Volt CMOS caller ID with

call waiting detection circuit. It can receive signals following Bellcore
GR-30-CORE & SR-TSV-002476, BT SIN227 & SIN242, and ETSI
ETS 300 788-1/-2 specifications.

The NW6006 provides 1200 baud Bell 202 and ITU-T V.23 FSK

demodulation, detection in stutter dial tone mode and CAS/DT-AS
detection. Two seperate differential input amplifiers allow the device to
be connected with both Tip/Ring and Telephone Hybrid receive pair.
FSK demodulation is implemented only on Tip/Ring, while DT-AS(or
CAS) detection can be on either Tip/Ring or Hybrid Receive. In
addition, NW6006 provides a serial FSK data interface via which the
data can be selected to be processed as a bit stream or extracted
from a 1 byte built-in buffer. An on-chip Stutter Dial Tone Detector is
provided to support the voice mail applications.

The device can be used in feature or cordless phones with voice

mail for BT Calling Line Identity Presentation (CLIP), CCA CLIP and
Bellcore Calling Identity Delivery (CID) systems. It can also be used in
caller ID boxes, modem, fax machines, answering machines,
database query systems and Computer Telephony Integration (CTI)
systems.

VREF

IN1+

OSCOUT OSCIN CB0 CB1 CB2

ST/GT

DR/STD

IN2+

Oscillator

Control Bit Decoder

Bias

Generator

Guard Time

Tone Alert

Detector

FSK

Demodulator

Data/Timing Recovery

Mux

PWDN

CASEN

FSKEN

MODE

GS1EN

GS2EN

FSKEN

MODE

GS1EN

GS2EN

SDTEN

Stutter Dial Tone

Detector

SDTEN

Mux

Figure 1. Block Diagram

FUNCTIONAL BLOCK DIAGRAM

IN1-

GS1

IN2-

GS2

EST

CD/STRDT

DCLK
DATA

INDUSTRIAL TEMPERATURE RANGE

NW6006 ENHANCED TYPE II CALLER ID DECODER
WITH STUTTER DIAL TONE DETECTOR

PIN INFORMATION

Figure 2. Pin Assignment

VREF

IN1+

IN1-

GS1

GND

OSCIN

OSCOUT

CB0

DCLK

DATA

IN2+
IN2-
GS2
CB2
CB1
VCC
CD/STRDT
ST/GT
EST
DR/STD

20
19
18
17
16
15
14
13
12

1
2
3
4
5
6
7
8
9
10

Name

Type

Pin No.

Description

VREF

Reference Voltage.

This output is used to bias the input OP amp. It is typically VCC/2.

IN1+

Non-inverting Input of the gain adjustable Tip/Ring OP amp.

IN1-

Inverting Input of the gain adjustable Tip/Ring OP amp.

GS1

Gain Select Output of the gain adjustable Tip/Ring OP amp.
The Tip/Ring signal can be attenuated or amplified at GS1 by adjusting the feedback resistor between GS1 and IN1-.

The FSK signal is always detected by Tip/Ring OP amp while DT-AS(CAS) signal can be detected by either Tip/Ring

or Hybrid OP amp. The OP amp selection is controlled by CB1 and CB2 bits.

GND

Ground.

OSCIN

Oscillator Input.

A 3.579545 MHz crystal or ceramic resonator should be connected between this pin and the OSCOUT. It can also
be driven by an external clock source.

OSCOUT

Oscillator Output.
A 3.579545 MHz crystal or ceramic resonator should be connected between this pin and the OSCIN. When an

external clock drives OSCIN, this pin can be left floating.

CB0

Control Bit 0 (FSK Data Interface Mode Select).

This pin can select the 3-wire FSK data interface mode. A `0' on this pin indicates interface mode 0; while a `1' on
this pin indicates interface mode 1. (The FSK data interface is consisted of DATA, DCLK and DR/STD pins.)

When CB0 is high and CB1, CB2 are both low, the device is set into the power down state.

DCLK

I/NC

Data Clock of the Serial FSK Interface.

In mode 0 (CB0 is low), this pin is unused; In mode 1 (CB0 is high), this pin is an input which clock the FSK data

byte out to the DATA pin.

DATA

Data Output of the Serial FSK Interface.

In mode 0 (CB0 is low), the FSK serial bit stream is output to the DATA pin directly.

In mode 1 (CB0 is high), the start bit is stripped off, the data byte and the stop bit is stored in a 9-bit buffer. At the
end of each word signaled by the DR/STD pin, the microcontroller should shift the byte out onto the DATA pin by

applying 8 read pulses to the DCLK pin. A 9

DCLK pulse will shift out the stop bit for framing error checking.

INDUSTRIAL TEMPERATURE RANGE

NW6006 ENHANCED TYPE II CALLER ID DECODER
WITH STUTTER DIAL TONE DETECTOR

Abbreviation Index

CAS

----------------------------------------------------------- CPE Alerting Signal

CDS

---------------------------------------------------------- Caller Display Service

CID

---------------------------------------------------------- Calling Identity Delivery

CIDCW

---------------------------------------------------------- Calling Identity Delivery on Call Waiting

CLIP

---------------------------------------------------------- Calling Line Identity Presentation

CNAM

--------------------------------------------------------- Calling Name Delivery

CND

--------------------------------------------------------- Calling Number Delivery

CNIC

---------------------------------------------------------- Calling Number Identification Circuit

---------------------------------------------------------- Central Office

DT-AS

---------------------------------------------------------- Dual Tone Alert Signal

MEI

---------------------------------------------------------- Multiple Extension Interworking

SDT

---------------------------------------------------------- Stutter Dial Tone

---------------------------------------------------------- Terminal Equipment

PIN INFORMATION (CONTINUED)

Name

Type

Pin No.

Description

DR/STD

O/NC

Data Ready or DT-AS Detection Delayed Steering Output.
This pin is active low. When FSK demodulation is enabled, this pin is the Data Ready output. In FSK interface mode 0,

this pin is unused and reads `1'. While in mode 1, this pin is normally high and goes low for half a bit time at the end of
a word. If DCLK starts during DR low, the first rising edge of the DCLK input will return DR to high. In this way, reading
of the first DATA bit can clear the interrupt requested by a low going DR.
When DT-AS detection is enabled, this pin is the Delayed Steering Output. An active low signal on this output indicates
the detection of a `guard time qualified' DT-AS.

EST

DT-AS Early Steering Output.
This pin is an active high output to indicate the detection of a raw DT-AS signal. It is used with the ST/GT pin and

external components to time qualify the detection.

ST/GT

I/O

DT-AS Detection Steering Input/Guard Time Output.

It's a CMOS output and an input of voltage comparator. It is used in conjunction with the EST pin and external
components to time qualify a raw DT-AS signal detection.
If the voltage at this pin is greater than the voltage threshold, DR/STD pin is asserted low to indicate that a DT-AS has
been detected. A voltage less than the threshold enable the device to accept a new DT-AS and return the DR/STD pin
to high.

CD/STRDT

FSK Carrier Detector or Stutter Dial Tone Detector Output.
This is an active low CMOS output signal to indicate the presence of in-band FSK signal or valid Stutter Dial Tone

signal.

VCC

3/5 V Power Supply.

CB1

Control Bit 1 (Function Select 1).
This pin is used with CB2 to select FSK demodulation, Tip/Ring DT-AS/Dial Tone detection, Hybrid DT-AS/Dial Tone
detection with or without Stutter Dial Tone Detection. See Table 1. When CB0 is high, CB1 and CB2 pins are both low,
the device is set into the power down state.

CB2

Control Bit 2 (Function Select 0).

This pin is used with CB2 to select FSK demodulation, Tip/Ring DT-AS/Dial Tone detection, Hybrid DT-AS/Dial Tone
detection with or without Stutter Dial Tone Detection. See Table 1. When CB0 is high, CB1 and CB2 pins are both low,
the device is set into the power down state.

GS2

Gain Select Output of the gain adjustable Hybrid OP amp.
The hybrid receive signal can be amplified or attenuated at GS2 by adjusting the feedback resistor between GS2 and
IN2-. When the CPE is off-hook, DT-AS detection of the GS2 signal should be enabled via the CB1 and CB2 pins.

IN2-

Inverting Input of the gain adjustable Hybrid OP amp.

IN2+

Non-inverting Input of the gain adjustable Hybrid OP amp.

INDUSTRIAL TEMPERATURE RANGE

NW6006 ENHANCED TYPE II CALLER ID DECODER
WITH STUTTER DIAL TONE DETECTOR

FUNCTIONAL DESCRIPTION

CALLER ID SPECS SUPPORTED

The NW6006 is a type II Caller ID device with Call Waiting

capability. It supports Bellcore, BT and ETSI specifications. The major
differences between above specs are as follows (see Fig. 11, Fig. 12
and Fig. 13 for reference):

BELLCORE AND TIA

Bellcore GR-30-CORE and SR-TSV-002476 define the

requirement for the signalling services of Calling Number Delivery
(CND), Calling Name Delivery (CNAM), VMWI (Visual Message
Waiting Indicator) and Calling Identity Delivery on Call Waiting
(CIDCW).

In CND or CNAM service, information of the calling party is

embedded in the silent interval between the first and second ringing.
The NW6006 can detect and demodulate the incoming Bell-202 FSK
data. In CIDCW service, information about an incoming caller is sent
to the subscriber who is engaged in another call. A CPE Alerting
Signal (CAS) indicates that a CIDCW data is incoming. The NW6006
can detect the alerting signal and demodulate the incoming FSK
information which contains CIDCW data. The demodulated data is
output onto the serial interface.

In North America, Telecommunications Industry Association (TIA)

Pin

Name

Description

CB0

FSK Data Interface Mode

Select

0
1

FSK Data Interface Mode 0: FSK bit stream is output directly.
FSK Data Interface Mode 1: FSK byte is stored in a 1-byte buffer, which can be

read serially by the microcontroller.

CB1

CB2

Function Select 1

Function Select 0

CB1

CB2

FSK Demodulation is enabled. Tip/Ring input (GS1) is selected. In FSK
Demodulation (CB0 = `1'), DR/STD is DR.

Hybrid DT-AS Detection is enabled. Hybrid Receive input (GS2) is selected.

DR/STD is STD.
When CB0 is high (`1'): Stutter Dial Tone Detection is enabled. CD/STRDT is

STRDT.
When CB0 is low (`0'): Stutter Dial Tone Detection is disabled. CD/STRDT is CD.

Tip/Ring DT-AS Detection is enabled. Tip/Ring input (GS1) is selected. DR/STD
is STD.
When CB0 is high (`1'): Stutter Dial Tone Detection is enabled. CD/STRDT is

STRDT.
When CB0 is low (`0'): Stutter Dial Tone Detection is disabled. CD/STRDT is CD.

Tip/Ring DT-AS detection is required for Bellcore MEI and BT on-hook CLIP.

When CB0 is high (`1'): the NW6006 will be powered down. It draws minimal

power supply current.

When CB0 is low (`0'): for factory testing only.

Table 1. Description of Control Bit Pins CB0-2

PIN INFORMATION (CONTINUED)

also defines standards. TIA specification TIA/EIA-716

defines Type I

CPE requirements. A type II CPE specification document is drafted
as TIA/EIA-777.

BRITISH TELECOM

BT SIN227 and SIN242 define the signal interface between the

Central Office (CO) and the Terminal Equipment (TE) for the Caller
Display Service (CDS). CDS provides CLIP (Calling Line Identity
Presentation) that delivers to an idle state (on hook) TE the identity of
an incoming caller before the first ring.

A polarity reversal on the A and B wires indicates the arrival of a

CDS call. After that comes an Idle State Tone Alert Signal, and then
Caller ID FSK information transmitted in ITU-T V.23 format. When the
subscriber is engaged in a call, the arrival of information about
another incoming call is indicated by a Loop State Tone Alert Signal.
The NW6006 can detect tone alert signal and demodulate the
incoming ITU-T V.23 FSK signals.

ETSI

The ETSI caller identity specifications ETS 300 788-1 for on-hook

and ETS 300 788-2 for off-hook define the requirements for CPE,
while ETS 300 659-1 for on-hook and ETS 300 659-2 for off-hook
define the end office requirements. The services such as CLIP and
CLIP with Call Waiting in ETSI specifications are similar to those of
Bellcore. The ETSI specifications are popularly used in Europe.

INDUSTRIAL TEMPERATURE RANGE

NW6006 ENHANCED TYPE II CALLER ID DECODER
WITH STUTTER DIAL TONE DETECTOR

BLOCK DESCRIPTION

The NW6006 requires a 3.579545 MHz system clock and consists

of four major functional blocks: Analog Input Circuit, Dual Tone Alert
Signal Detection, Stutter Dial Tone Detection and FSK Demodulation.

ANALOG INPUT CIRCUIT

The input signal is processed by the Analog Input Circuit block,

which is comprised of two OP amps and a bias source (VREF). VREF
is the output of a low impedance voltage source used to bias the input
OP amp, and is typically equal to VCC/2. The Tip/Ring OP amp
(IN1+, IN1-, GS1 pins) is for connecting to Tip and Ring, while the
Hybrid OP amp (IN2+, IN2-, GS2 pins) is for connecting to Hybrid
Receive Pair. The gain adjustable OP amps are also used to select
the input gain by connecting a feedback resistor between GS and the
IN- pin. Fig. 3 shows the differential input configuration. In single-
ended configuration, the gain adjustable OP amp is connected as
shown in Fig. 4.

NW6006

REF

IN+
IN-

Differential Input Amplifier
C1=C2
R1=R2 (For unity gain R5=R2)
R3=(R4R5)/(R4+R5)

Voltage Gain
Av = R5/R2
Input Impedance

Zin =2

+ (1/

Figure 3. Differential Input Gain Control Circuit

Rin

NW6006

IN+

IN-

REF

Voltage Gain
Av = Rf / Rin

Figure 4. Single-ended Input Gain Control Circuit

DT-AS DETECTION ON EITHER TIP/RING OR HYBRID
RECEIVE PAIR

In off-hook services, the detection of Dual Tone Alert Signal (DT-AS)

will affect the quality of the call waiting service. Even though the end
office has muted the far end party before and after it sends DT-AS, the
near end user who is to receive the FSK information may be still
talking. Therefore, the CPE must be able to detect DT-AS successfully
in the presence of near end speech. Furthermore, imitation of DT-AS
by speech will also affect the DT-AS detector, thus false detection may
be generated.

To achieve better DT-AS detection quality, a method is to put DT-AS

detection on the telephone hybrid receive pair instead of on Tip/Ring.
As the near end speech has been attenuated while the DT-AS level is
the same as on Tip/Ring, the DT-AS immunity is improved.

A CPE capability called Multiple Extension Interworking, in process

of being defined by Bellcore, requests the CPE be capable of detecting
DT-AS when the line is off-hook, although the CPE itself may be on-
hook. Under some conditions, an on-hook CPE may send an
acknowledgment to the end office. Also, the on-hook CPE's capability
of detecting DT-AS enables the call logs between on and off-hook
CPEs to be maintained synchronous. In this way, when all off-hook
CPEs are MEI compatible and DT-AS is received, one of the CPEs will
send the acknowledgment signal and all CPEs will receive FSK.

Therefore, if the DT-AS detector is connected only to the hybrid

receive pair, the CPE can not detect DT-AS when it is on-hook. When
the CPE is on-hook, either the hybrid is non-functional or the signal
level is severely attenuated. Thus, an on-hook CPE must be able to
detect DT-AS from Tip/Ring.

The NW6006 provides two input OP amps via which the device can

be connected both to Tip/Ring and to the Hybrid Receive pairs. Both
connection can be differential or single-ended. FSK demodulation is
implemented only on Tip/Ring, while DT-AS detection can be on either
Tip/Ring or Hybrid Receive. Tip/Ring DT-AS detection is required for
MEI and BT's on-hook CLIP.

It should be noted here that as the Hybrid OP amp is for DT-AS

detection only, its gain can always be adjusted specifically for the DT-
AS signal.

STUTTER DIAL TONE SPECS SUPPORTED

The NW6006 also supports TIA/EIA Stutter Dial Tone specification

PN-4159 Draft. This specification defines the requirement for the
singalling of Stutter Dial Tone (SDT). When there is a message waiting
in a customer's voicemail box, the serving telephone company's
Central Office (CO) switch may apply a SDT signal to the customer's
line when it is taken off-hook. An SDT CPE is used to automatically
detect the SDT in response to an on-hook to off-hook transition and
provide an indication.

INDUSTRIAL TEMPERATURE RANGE

NW6006 ENHANCED TYPE II CALLER ID DECODER
WITH STUTTER DIAL TONE DETECTOR

DUAL TONE ALERT SIGNAL DETECTION

The Dual Tone Alert Signal is used only in off-hook signalling in

Bellcore system and ETSI system, but in BT system it is used in both
on and off-hook signalling. The low and high tone frequencies of three
different systems are as follows:

When the device selects DT-AS detection, the bi-purpose output

pin DR/STD is STD. STD goes low when DT-AS has been detected
and return high after DT-AS has ended.

The incoming Alert Signal goes through anti-alias filter and then is

separated into high band and low band by two bandpass filters. The
tone detection algorithm examines the filter outputs to validate the
arrival of the DT-AS. The EST pin becomes active when both tones
are detected. The EST is only the preliminary indication, it must be
qualified by the "guard time" as required by Bellcore, BT and ETSI (a
minimum duration for valid signals). STD is the guard time qualified
DT-AS detection output, it indicates the correct detection.

Fig. 5 shows the operation of the guard time circuit and Fig. 6

shows the waveform of the EST, ST/GT and STD pins. The total
recognition time is t

REC

= t

+ t

, where t

is the tone present detection

time and t

is the tone present guard time. The total absent time is t

ABS

= t

+ t

, where t

is the tone absent detection time and t

is the tone

absent guard time. The guard time is the RC time constant for the
capacitor charge to VCC or discharge to GND. To get the unequal
present and absent guard time, a diode can be connected as shown
in Fig. 7 to provide different RC time constant (varying resistance
value) during charging and discharging.

Figure 7. Guard Time Circuits with Unequal Present and

Absent Times

> t

=R1CIn(VCC/(VCC-V

TGT

))

CIn((VCC-Vd(R

/R2))/

TGT

-Vd(R

/R2)))

=R1R2/(R1+R2)

Vd=diode forward voltage

GP <

CIn((VCC-Vd(R

/R2))/

(VCC-V

TGT

-Vd(R

/R2)))

=R1CIn(VCC/V

TGT

)

=R1R2/(R1+R2)

Vd=diode forward voltage

Bellcore & ETSI

Low Tone

Frequency

2130 Hz ± 1.1% (on-hook)
2130 Hz ± 0.6% (off-hook)

2130 Hz ± 0.5%

High Tone

Frequency

2750 Hz ± 1.1% (on-hook)

2750 Hz ± 0.6% (off-hook)

2750 Hz ± 0.5%

Figure 5. Guard Time Circuit of Dual Tone Alert Signal

Detection

Alerting Signal

TGT

REC

ABS

DT-AS

EST

ST/GT

STD

Switch

Figure 6. Guard Time Waveform

NW6006

VCC

ST/GT

EST

NW6006

VCC

ST/GT

EST

NW6006

Dual tone detected

VCC

Comparator

TGT

ST/GT

EST

STD

INDUSTRIAL TEMPERATURE RANGE

NW6006 ENHANCED TYPE II CALLER ID DECODER
WITH STUTTER DIAL TONE DETECTOR

STUTTER DIAL TONE DETECTION

In some specifications, Stutter Dial Tone is used to indicate voice

mails. The low and high tone frequencies of Stuttered Dial Tone signal
are 350 Hz (tolerant range: 343 Hz to 357 Hz) and 440 Hz (tolerant
range: 431 Hz to 449 Hz).

When the device selects Stutter Dial Tone detection, the bi-

purpose output pin CD/STRDT is STRDT. STRDT goes low when dial
tone signal has been detected and return high after dial tone signal
has been ended (see Fig. 21).

The incoming Stuttered Dial Tone signal goes through anti-alias

filter and then is separated into high band and low band by two
bandpass filters. The tone detection algorithm examines the filter
outputs to validate the arrival of the Stutter Dial Tone signal. An
embeded digital algorithm implements guard-time function. If the dial
tone signal is qualified by the algorithm, the STRDT pin goes active to
indicate a correct detection.

FSK DEMODULATION

The key part among the functions offered by NW6006 is FSK

demodulation. This function is implemented by several stages: first,
the carrier detector provides an indication of the presence of signal at
the bandpass filter output; second, the device's dual mode serial
interface allows convenient extraction of the 8-bit data words in the
demodulated FSK bit stream.

The FSK characteristics are different in BT, ETSI and Bellcore

specifications. The signal frequencies in BT and ETSI correspond to
ITU-T V.23; the Bellcore frequencies correspond to Bell 202. The
NW6006 is compatible with both formats. It also meets the signal
characteristics by setting the Tip/Ring input OP amp at unity gain in 5V
operation.

ITU-T V.23

Bell 202

Mark Freq. (`1')

1300 Hz ± 1.5%

1200 Hz ± 1%

Space Freq. (`0')

2100 Hz ± 1.5%

2200 Hz ± 1%

For 3 V operation, the FSK receiver becomes easier to accept

lower level signals than in 5 V operation. The Tip/Ring input OP amp
gain should be reduced to maintain the FSK reject level.

Serial FSK Interface

The three wire DATA, DCLK and DR form the data interface of the

FSK demodulation. The DATA pin is the serial data pin that outputs
data to external devices. The DCLK pin is the data clock which is used
in Mode `1' and is generated by an external device. The DR pin is the
data ready signal used in Mode `1', also an output from the NW6006
to external devices. DR/STD pin is a dual purpose output pin, when
FSK function is selected it is DR.

Two modes are selectable via control of the device's CB0 pin:

Mode `0' (CB0 is low), where the FSK bit stream is output directly;
Mode `1' (CB0 is high), where the data byte and the stop bit are stored
in a 9 bit buffer.

Mode `0' (CB0 is low)

In this mode, the device demodulates the incoming FSK signal,

and output the data directly to the DATA pin. DCLK and DR pins are
unused. Fig. 19 and Fig. 20 show the timing diagram of Mode `0'
operation.

Mode `1' (CB0 is high)

In this mode, the received byte is stored on chip. The

microcontroller supplies read pulses (DCLK) to shift the register
contents serially out of the NW6006, onto the DATA pin. The NW6006
asserts DR to denote the word boundary and indicate to the
microprocessor that a new word has become available. Internal to the
device, the demodulated data bits are sampled and stored. Midway
through the stop bit, the 8 data bits and the stop bit are parallel loaded
into an 9-bit shift register and DR goes low. The contents of register
are shifted out to DATA pin on DCLK's rising edge with LSB (Least
Significant Bit) out first. If DCLK begins while DR is low, DR will return to
high upon the first DCLK rising edge. This feature allows the

associated interrupt to be cleared by the first read pulse. Otherwise,

DR stays low for half a nominal bit time (1/2400 sec) and then returns
to high. After the last bit (Most Significant Bit) has been read,
additional DCLKs are ignored. Fig. 18 shows the timing diagram of
Mode `1' operation.

Reading the stop bit is a method of checking framing errors. If it's

certain that there is no framing error would occur, the microcontroller
only needs to send 8 DCLK pulses to shift the data byte out. After the
checksum byte has be received, all 9 bits should be read and framing
error checked.

INDUSTRIAL TEMPERATURE RANGE

NW6006 ENHANCED TYPE II CALLER ID DECODER
WITH STUTTER DIAL TONE DETECTOR

OTHER FUNCTIONS

Power-down Mode

The device provides the power-down feature to reduce the power

consumption. Power-down can be activated by setting Control Bits 0-2
to `100'. Note that momentary transition of CB0-2 into the power-down
code won't activate power-down but will reset the device.

In this mode, both input OP amps, reference voltage and the

oscillator are non functional. When the device is in power-down, DATA,

DR/STD, CD/STRDT are high; EST and ST/GT are low.

An intelligent Power-down feature is implemented to further reduce

the operating current. When FSK is selected, DT-AS detector and
Stuttered Dial Tone Detection are powered down. When DT-AS and
STRDT are selected, FSK demodulator is powered down. The Tip/
Ring and Hybrid input OP amps are not affected in the intelligent
Power-down.

Crystal Oscillator

A 3.579545 MHz crystal oscillator or other external clock source is

required for NW6005. The crystal can be directly connected between
OSCIN and OSCOUT pins without any external component. If an
external clock source is used, OSCIN pin should be driven by the
clock source and OSCOUT pin is left floating or is used to drive other
devices. Fig. 8 shows some applications.

FSK CARRIER DETECTION

The carrier detector detects the presence of a signal of sufficient

amplitude at the output of the FSK bandpass filter. If the signal is
qualified by a digital algorithm, it set the CD output to low indicating a
successful carrier detection. NW6006 supplies a 10 ms hysteresis to
allow for momentary signal drop out once CD has been activated.
When there is no activity at the FSK bandpass filter output for 10 ms,

CD is released.

When CD is inactive (high), the raw output of the FSK

demodulator is ignored by the FSK data output interface. In mode`0',
the DATA pin is forced high. In mode `1', the internal shift register is not
updated. If DCLK is clocked, DATA is undefined.

Since signals such as DT-AS, DTMF tones and speech are within

the FSK frequency band and thus may activate the carrier detector.
The NW6006 should be put into DT-AS or power down mode when
FSK is not expected to avoid false carrier detection and false
demodulation.

to the next device

(b) Common Crystal Connection of Several Devices
Sharing One Timing Source

(a) Connection of One Device with Crystal Oscillator

NW6006

OSCIN

OSCOUT

3.579545MHz

NW6006

OSCIN

OSCOUT

NW6006

OSCIN

OSCOUT

NW6006

OSCIN

OSCOUT

3.579545MHz

Figure 8. Applicaiton of Clock Driven Circuit

APPLICATION NOTE

CONTROL BITS PROGRAMMING

Functionality of the NW6006 can be selected by coding CB0-CB2,

as shown in Table 2.

Table 2. Control Bits Programming

Functionality Group

CB0

CB1

CB2

FSK Demodulation Mode 0

FSK Demodulation Mode 1

Hybrid DT-AS Detection with Stuttered
Dial Tone Detection

Hybrid DT-AS Detection Only

Tip/Ring DT-AS Detection with Stuttered
Dial Tone Detection

Tip/Ring DT-AS Detection Only

Power Down

Factory Test Only

HYBRID CONNECTION

To optimize the device's talkdown and talkoff performance, Hybrid

connection is recommended. There are two Op Amps in NW6006
which bring convenience for Hybrid connection. When connected to
the Hybrid Op Amp, the Hybrid circuit will attenuate the speech signal
at least 9 dB from the microphone to the speaker, which leads a much
better performance of near-end talkdown and talkoff.

It is highly recommended to demodulate the FSK signal using the

Tip/Ring OP Amp and to detect the CAS signal using the Hybrid OP
Amp. This implementation brings not only optimized talkdown and
talkoff performance, but also the convenience to adjust FSK and CAS
sensitivity separately.

INDUSTRIAL TEMPERATURE RANGE

NW6006 ENHANCED TYPE II CALLER ID DECODER
WITH STUTTER DIAL TONE DETECTOR

GAIN SETTING

Ideally, the gain of the two Op Amps would be set to 0 dB. But in

real applications, the gain setting should be determined by industry
standards as well as by customer requirements. The circuit and
calculation method of gain setting is illustrated in Figs. 3 and 4. For
Hybrid connection, the single-ended solution (Fig. 4) is often selected.

Typically, the CAS sensitivity should be lower than the FSK

sensitivity in order to prevent missing the FSK signal while the CAS
signal is detected. Therefore, it is suggested to set the gain of the Op
Amp for FSK demodulation 3 dB higher than that of the Op Amp for
CAS detection.

THE DIFFERENCE BETWEEN FSK MODE 0 AND MODE1

In FSK mode 0, the FSK serial bit stream is output to the DATA pin

directly. DCLK and DR pins are unused. The microcontroller reads out
the data by the serial data interface which is implemented by software
programming. The flexibility of using software improves the immunity
to interference.

In FSK mode 1, the received byte is stored in an on-chip register.

The microcontroller supplies read pulses (DCLK) to shift the register
contents serially out of the NW6006, onto the DATA pin. The DR pin is
also used to indicate the word boundary.

VALID DT-AS EVALUATION

DT-AS output will generate false detection if being interfered by

speech. In this way, valid DT-AS pulse evaluation becomes necessary.
The evaluation defines a minimum and maximum pulse duration,
and maximum drop out time within that pulse duration. See Figure 22
for reference.

INDUSTRIAL TEMPERATURE RANGE

NW6006 ENHANCED TYPE II CALLER ID DECODER
WITH STUTTER DIAL TONE DETECTOR

APPLICATION INFORMATION

Figure 9. Typical Application Circuit For Bellcore MEI Compatible Type II Telephone

with Stutter Dial Tone Detection, 5 V Operation

NW6006

VREF

IN1+

IN1-

GS1

GND

OSCIN

OSCOUT

CB0

DCLK

DATA

IN2+

IN2-

GS2

CB2

CB1

VCC

STRDT

ST/GT

EST

STD

Telephone

Hybrid

TIP

RING

Tx+

Tx-

Rx-

Rx+

Speaker

TIP

RING

39k

470k

56k

GND

470k

2n2

56k

330k

100n

100n, 20%

VCC= 5V +/-10%

FSK Interface Mode 1 is selected

Xtal

To Microcontroller

From Microcontroller

470k

Microphone

Note:
1. Resistors are 1%, 0.1Watt; Unless stated, capacitors are 5%, 6.3 V.
2. All diodes in the circuit are 1N4148 or equivalent.
3. Xtal is 3.579545 MHz, 0.1% crystal or ceramic resonator.
4. Tip/Ring op amp gain = 0 dB; Hybrid Receive op amp gain = -3 dB.
5. For 1000 Vrms, 60 Hz isolation from Tip to Earth and Ring to Earth:
R1, R2 = 430 k, 0.5 W, 5%, 500 V min. C1, C2 = 2n2, 250 V min.
6. For BT application, R3=R4= 422k;
For Bellcore application, R3=825k, R4=226k.

INDUSTRIAL TEMPERATURE RANGE

NW6006 ENHANCED TYPE II CALLER ID DECODER
WITH STUTTER DIAL TONE DETECTOR

Figure 10. Typical Application Circuit For Bellcore MEI Compatible Type II Telephone

with Stutter Dial Tone Detection, 3 V Operation

NW6006

VREF

IN1+

IN1-

GS1

GND

OSCIN

OSCOUT

CB0

DCLK

DATA

IN2+

IN2-

GS2

CB2

CB1

VCC

CD/STRDT

ST/GT

EST

DR/STD

Telephone

Hybrid

TIP

RING

Tx+

Tx-

Rx-

Rx+

Speaker

TIP

RING

39k

282k

56k

GND

470k

2n2

56k

200k

100n

100n, 20%

VCC= 3V +/-10%

FSK Interface Mode 1 is selected

Xtal

To Microcontroller

From Microcontroller

282k

Microphone

INDUSTRIAL TEMPERATURE RANGE

NW6006 ENHANCED TYPE II CALLER ID DECODER
WITH STUTTER DIAL TONE DETECTOR

..101010..

Data

...

PWDN

FSKEN

DCLK

DATA

Ch. Seizure

Mark

Message

Alerting Signal

A/B Wires

1st Ringing

2nd Ringing

Figure 11. Bellcore On-hook Data Transmission Timing Diagram

Notes:
1) A= 2 sec typ., B= 250 - 500 ms, C= 250 ms, D= 150ms, E depends on data length, Max C+D+E = 2.9 - 3.7 sec, F

200 ms.

2) In a battery operated CPE, NW6006 may be enabled only after the end of ringing to conserve power.
3) The microcontroller in the CPE powers down the NW6006 after CD goes inactive.
4) The microcontroller times out if CD is not activated on the 2nd ring and puts the device into Power-down mode.
5) FSK may be always enabled while the CPE is on-hook. To prevent the FSK demodulator from reacting to other inband signals such as speech, DT-AS or DTMT tones. The designer may
choose to disable FSKduring the period that FSK signal is not expected.
6) PWDN and FSKEN are internal signals decoded from Control Bits CB2-0.
7) When CB0 is low, both DR and DCLK pins are unused.

Note 2

Note 1

Note 2

Note 3

Note 4

Note 5

Note6

Note 7

INDUSTRIAL TEMPERATURE RANGE

NW6006 ENHANCED TYPE II CALLER ID DECODER
WITH STUTTER DIAL TONE DETECTOR

CAS

Mark

Message

CPE off-hook

CPE mutes handset and
disable keypad

CPE unmutes handset and
enable keypad

A/B wires

PWDN

FSKEN

CPE sends

ACK

STD

...

Data

DCLK

DATA

Hybrid

DT-ASEN

Notes:
1) A= 75 - 85 ms, B= 0 -100 ms, C= 55 - 65 ms, D= 0 - 500 ms, E= 58 - 75ms, F depends on data length, G

50 ms.

2) If AC power is not available, the designer may use the line power when the CPE goes off-hook and use battery power while on-hook. The CPE should also be CID (on-hook) capable .
3) If the end office fails to send the FSK signal, the CPE should disable FSKEN and unmute the handset and enable the keypad after this interval.
4) When FSK signal is not expected, the FSKEN should be set low to disable the FSK demodulator.
5) FSKEN should be high as soon as the CPE has finished sending the acknowledgement signal ACK.
6) FSKEN should be low when CD become inactive.
7) PWDN, FSKEN and Hybrid DT-ASEN are internal signals decoded from Control Bits CB2-0.
8) When CB0 is low, both DR and DCLK pins are unused.

Note 1

Note 2

Note 3

Note 4

Note 5

Note 6

Figure 12. Bellcore Off-hook Data Transmission Timing Diagram

Note7

Note8

INDUSTRIAL TEMPERATURE RANGE

NW6006 ENHANCED TYPE II CALLER ID DECODER
WITH STUTTER DIAL TONE DETECTOR

Alerting

Signal

Ch. Seizure

Mark

Message

Ring

..101010..

Data

...

Line Reversal

A/B Wires

PWDN

STD

TE DC load

TE AC load

FSKEN

DCLK

DATA

15 ±1 ms

20 ±5 ms

<120

50 - 150 ms

< 0.5 mA (optional)

Current Wetting Pulse

Zss

Tip/Ring

DT-ASEN

Note 1

Note 2

Note 3

Note 4

Notes:
1) A

100ms, B=88 - 110 ms, C

45 ms (up to 5 sec), D= 80 -262 ms, E= 45 - 75 ms, F

2.5 sec (typ. 500 ms), G

200 ms.

2) By choosing t

=15 ms, t

ABS

will be 15-25 ms (refer to Fig. 8). Current wetting pulse and AC/DC load should be applied right after the STD rising edge.

3) AC and DC loads should be removed between 50-150 ms after the end of the FSK signal. The NW6006 may go to power down mode to save power.
4) FSKEN should be set low to disable the FSK demodulator, when the FSK signal is not expected.
5) Tip/Ring DT-ASEN, PWDN and FSKEN are internal signals decoded from Control Bits CB2-0.
6) When CB0 is low, both DR and DCLK pins are unused.

Figure 13. BT Idle State (on-hook) Data Transmission Timing Diagram

Note 5

Note 6

INDUSTRIAL TEMPERATURE RANGE

NW6006 ENHANCED TYPE II CALLER ID DECODER
WITH STUTTER DIAL TONE DETECTOR

MAXIMUM RATING

- Exceeding the following listed values may cause permanent damage.

Power Supply Voltage: -0.3 V to 6 V
Voltage on any pin other than supplies: GND - 0.3 V to VCC + 0.3 V
Current at any pin other than supplies:

10 mA

Storage Temperature: -65 °C to +150 °C

RECOMMENDED OPERATING CONDITIONS

Operating Temperature: -40 °C to +85 °C
Power Supply Voltage: 3 V ± 10% or 5 V ± 10%
Clock Frequency: 3.579545 MHz ± 0.1%
Input Voltage: 0 V to VCC

CRYSTAL SPECIFICATIONS

Frequency: 3.579545 MHz
Resonancy tolerance: ± 0.1%( -40°C to +85°C)
Resonance mode: Parallel
Load capacitance: 18 pF
Maximum series resistance: 150

Maximum drive level: 2 mW

DC ELECTRICAL CHARACTERISTICS

Test 1: All inputs are VCC/GND except for oscillator pins. No analog input. Output unloaded. NW6006 in power down mode.
Test 2: All inputs are VCC/GND except for oscillator pins. No analog input. Ouput unloaded. FSK is enabled.

Parameter

Pin

Description

Min

Typ

Max

Units

Test Conditions

CCS

Power Supply Standby
Current

0.5

Test 1

VCC

Operating Supply Current
VCC = 5 V

10%

VCC = 3 V

10%

2.5
1.8

3.8
2.7

mA
mA

Test 2

T+

Schmitt Trigger Input High
Threshold

0.5VCC

0.7VCC

T-

DCLK

Schmitt Trigger Input Low
Threshold

0.3VCC

0.5VCC

HYS

Schmitt Hysteresis

0.2

CB0
CB1

CMOS Input High Voltage

0.7VCC

VCC

CB2

CMOS Input Low Voltage

GND

0.3VCC

DCLK, DATA, EST

DR/STD, CD, ST/GT

Output High Sourcing
Current

-0.8

=0.9VCC

INDUSTRIAL TEMPERATURE RANGE

NW6006 ENHANCED TYPE II CALLER ID DECODER
WITH STUTTER DIAL TONE DETECTOR

Parameter

Pin

Description

Min

Typ

Max

Units

Test Conditions

DCLK, DATA

DR/STD, CD

EST, ST/GT

Output Low Sinking

Current

= 0.1VCC

Iin1

IN1+, IN1-

IN2+, IN2-

Input Current

Iin2

DCLK

CB0, CB1, CB2

Input Current

= VCC to GND

ST/GT

Output High Impedance

out

= VCC to GND

VREF

Output Voltage

0.5VCC-0.1

0.5VCC+0.1

No Load

RREF

VREF

Output Resistance

TGT

ST/GT

Comparator Threshold
Voltage

0.5VCC-0.05

0.5VCC+0.05

DC ELECTRICAL CHARACTERISTICS (CONTINUED)

Parameter

Description

Min

Typ

Max

Units

Notes

Low Tone Frequency

2130

Nominal frequency

High Tone Frequency

2750

Nominal frequency

FDA

Frequency Deviation Accept

1.1%

Within this range, tones are accepted.

FDR

Frequency Deviation Reject

3.5%

Outside this range, tones are rejected.

SIGAC

Accept Signal Level per tone

-40

-2

dBV

SIGRJ

Reject Signal Level per tone
(VCC = 5 V

10%, 3 V

10%)

-47

dBV

Input op amp configured to 0 dB gain for
5 V operation, gain for 3 V operation is
TBD. Signal level is per tone.

Positive and Negative Twist Accept #

SNR

Signal to Noise Ratio ##

AC ELECTRICAL CHARACTERISTICS

DUAL TONE ALERT SIGNAL DETECTION

# Twist = 20 |log ( f

amplitude / f

amplitude )|.

## Both tones have the same amplitude and at nominal frequencies. Band limited random noise 300-3400 Hz. Measurement valid only when tone is present.

Parameter

Description

Min

Typ

Max

Units

Notes

Low Tone Frequency

350

Nominal frequency

High Tone Frequency

440

Nominal frequency

FDA

Frequency Deviation Accept
High Tone
Low Tone

-7
-9

7
9

Within this range, tones are accepted.

FDR

Frequency Deviation Reject
High Tone
Low Tone

-13
-11

13
11

Outside this range, tones are rejected.

SIGAC

Accept Signal Level per tone

-31

-12

dBV

SIGRJ

Reject Signal Level per tone
(VCC = 5 V

10%, 3 V

10%)

-36

dBV

Input op amp configured to 0 dB gain for
5 V operation, gain for 3 V operation is
TBD. Signal level is per tone.

Positive and Negative Twist Accept #

-6

SNR

Signal to Noise Ratio ##

STUTTER DIAL TONE SIGNAL DETECTION

INDUSTRIAL TEMPERATURE RANGE

NW6006 ENHANCED TYPE II CALLER ID DECODER
WITH STUTTER DIAL TONE DETECTOR

AC ELECTRICAL CHARACTERISTICS (CONTINUED)

GAIN ADJUSTABLE OP AMP

Parameter

Description

Min

Typ

Max

Units

Test Conditions

Input Leakage Current

GND

VCC

Input Resistance

Input Offset Voltage

PSRR

Power Supply Rejection Ratio

1kHz ripple on VCC

CMRR

Common Mode Rejection

CMmin

CMmax

VOL

DC Open Loop Voltage Gain

Unity Gain Bandwidth

0.3

MHz

Output Voltage Swing

0.5

VCC -0.5

Load

100 k

Maximum Capacitive Load (GS)

Maximum Resistive Load (GS)

100

Common Mode Range Voltage

1.0

VCC-1.0

FSK DETECTION

Parameter

Description

Min

Typ

Max

Units

Notes

Input Detection Level

-40

-6.5

dBV

Reject Signal Level

-48

dBV

Production tested at VCC =3V

10%, or 5V

10%. Both mark and space have the same

amplitude.

Transmission Rate

1188

1200

1212

baud

FMARK

Input Frequency Detection
Bell 202 `1' (mark)

1188

1200

1212

FSPACE

Input Frequency Detection
Bell 202 `0' (space)

2178

2200

2222

FMARK

Input Frequency Detection
ITU-T V.23 `1' (mark)

1280.5

1300

1319.5

FSPACE

Input Frequency Detection
ITU-T V.23 0 (space)

2068.5

2100

2131.5

Positive and Negative Twist Accept

-10

SNR

Signal to Noise Ratio

Both mark and space have the same amplitude
and at nominal frequencies. Band limited
random noise: 200-3400 Hz. Present only when
FSK signal is present. #

# BT band is 200-3400 Hz, while Bellcore band is 0-4 kHz.

Notes:
dBV = decibels above or below a reference voltage of 1 Vrms.

INDUSTRIAL TEMPERATURE RANGE

NW6006 ENHANCED TYPE II CALLER ID DECODER
WITH STUTTER DIAL TONE DETECTOR

AC TIMING CHARACTERISTICS

POWER UP/DOWN AND FSK DETECTION

Parameter

Description

Min

Typ

Max

Units

Test Conditions

Power Up Time

Power Down Time

Input FSK to CD low delay

Input FSK to CD high delay

Hysteresis

DUAL TONE ALERT SIGNAL

Parameter

Description

Min

Typ

Max

Units

Test Conditions

Alert Signal Present Detect Time

Alert Signal Absent Detect Time

0.1

Power down is

enabled by

Control Bits

OSCOUT

Figure 14. Power Up/Down Timing

Figure 15. FSK Detection Time

Tip/Ring

FSK Signal

Tip/Ring

or Hybrid

Receive Pair

EST

Alert Signal

Figure 16. Dual Tone Alert Signal Detection Time

INDUSTRIAL TEMPERATURE RANGE

NW6006 ENHANCED TYPE II CALLER ID DECODER
WITH STUTTER DIAL TONE DETECTOR

Parameter

Description

Min

Typ

Max

Units

Test Conditions

t11

DCLK Cycle Time

t12

DCLK High Time

0.3

t13

DCLK Low Time

0.3

t14

DCLK Rise Time

100

t15

DCLK Fall Time

100

t16

DCLK Low Setup to DR

500

t17

DCLK Low Hold Time after DR

500

AC TIMING CHARACTERISTICS (CONTINUED)

SERIAL INTERFACE (MODE `1')

DCLK

t13

t14

t12

t15

t11

Figure 17. DCLK Timing in Mode `1'

Figure 18. Serial Data Interface Timing in MODE `1'

Notes:
1. DCLK clears DR.
2. DR not cleared by DCLK, low for a maximum time of 1/2 bit width.

stop b0 b1

stop

start

stop

Nth byte

(N-1)th byte

Nth byte

(N+1)th byte

t16

t17

Internal

Demodulated Bit

Stream

DCLK

DATA

note 1

note 2

start

b2 b3 b4 b5 b6 b7

stop

INDUSTRIAL TEMPERATURE RANGE

NW6006 ENHANCED TYPE II CALLER ID DECODER
WITH STUTTER DIAL TONE DETECTOR

AC TIMING CHARACTERISTICS (CONTINUED)

b0 b1 b2 b3 b4 b5 b6 b7 1

b0 b1

b0 b1 b2 b3 b4 b5 b6 b7

b0 b1 b2

TIP/RING

DATA

stop

start

t21

Nth byte

(N+1)th byte

Nth byte

(N+1)th byte

Figure 20. Serial Data Interface Timing in MODE `0'

Parameter

Description

Min

Typ

Max

Units

Test Conditions

Data Rate

1188

1200

1212

baud

t21

Input FSK to DATA Delay

t22

DATA Rise Time

200

t23

DATA Fall Time

200

SERIAL INTERFACE (MODE `0')

Test conditions:
1. FSK input data at 1200 ±

12 buad.

2. Load of 50 pF.

DATA

t23

t22

Figure 19. DATA Output Timing in Mode `0'

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