Datasheet XEISDNP Datasheet (XECOM)

XEISDNP

Single Module ISDN Analog Telephone

(POTS) Equipment Interface

Description

The XEISDNP is a multichip module designed
to interconnect analog telephone equipment such
as a handset, a Group 3 Fax machine, or an
analog modem to an ISDN Terminal Adapter. The
device provides all the functions needed to
support conventional analog subscriber equip­ment including voice/fax data CODEC, DTMF
tone detector, RING signal generator and tele­phone line power feed. It provides a simple,
compact solution for designers who wish to inte­grate an ISDN digital interface into their designs
but also protect their user’s investment in their
existing POTS (Plain Old Telephone Service)
equipment.

The XEISDNP is designed to interface with the
XECOM XEISDNU Single Module ISDN Terminal
Adapter.

Features

• Small size: 2.75" x 1.38" x 0.42"

• Adds POTS function to XECOM XEISDNU

• Supports standard analog telephones, Group 3
FAX machines, and analog modems

• Provides all Central Office functions to analog
telephone equipment

• Uses GCI (IOM-2) or IDL standard communi­cation bus to exchange voice/fax/data between
its on board CODEC and ISDN Terminal
Adapter

• Pin configurable to Mu-law or A-law PCM
coding

• Programmable for B1 or B2 channel of the
ISDN Basic Rate interface

• Uses standard data bus to access DTMF
codes from the ISDN TA

• Built-in 150V DC inverter to support RING
signal generation

• Built in power supply provides the telephone
handset with 30 to 50 mA current

RING GeneratorDC Power supply

10uF/250V

+

To telephone set
or FAX machine

CODEC

Voice/FAX

for

Data

DTMF

Decoder

GCI or IDL Bus

Three state

DTMF ready

DTMF output

Off Hook Power CTRL RING CTRL

Voice/FAX/Modem signal path (Analog)

ROUTE

SWITCH

Route CTRL

Page 2 XEISDNP

Mechanical Specifications

INCHES METRIC (MM)

MIN MAX MIN MAX

A

2.740 2.760 69.60 70.10

B

1.370 1.390 34.80 35.31

C

0.420 0.430 10.67 10.92

D

1.190 1.210 30.23 30.73

E

2.290 2.310 58.17 58.67

F

0.125 0.200 3.18 5.08

G

0.080 0.100 2.03 2.54

H

0.215 0.235 5.46 5.97

I

0.090 0.110 2.29 2.79

J

0.020 0.025 0.51 0.64

(Total pin count is 24 per side view.)

Pin Configuration

(Blank pin location indicates no pin installed)

TTIP

RING

DC_OUT

NC

DR/RXDIN

DT/TXD1

FST/CD1N

FSR/TXD3

NC
NC

OH

DTMF_RDY

RING_EN

RING_DC

PWR_CTRL

ROUTE_CT

/PDI/DREQ

D4
D5
D6
D7

-12V
GND

++5V
GND
B_M_CLK/RCLK
GND

GND
Mu/A
NC
+12V

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24

48
47
46
45
44
43
42
41
40
39
38
37
36
35
34
33
32
31
30
29
28
27
26
25

XEISDNP Page 3

Pin Descriptions

Name Pin # Direction Description

TIP 1 I/O Connect to POTS equipment

RING 2 I/O Connect to POTS equipment

DC_OUT 3 Output Test pin for the 150V DC supply for RING signal. Bypass to GND

with 10uF/250V capacitor.
NP 4, 29-44 No pin installed
NC 5,10,11,26 No connection allowed

DR/RXDIN 6 Input Data Receive for IDL or GCI

DT/TXD1 7 Output Data Transmit for IDL or GCI

FST/CDIN 8 Input Frame Synchronize Transmission: This pin accepts an 8KHz

clock that synchronizes the output of the serial PCM data at the

DT pin.

FSR/TXD3

(B2/B1)

9 Input When an ISDN mode (IDL or GCI) has been selected with

BCLKR, this pin selects either B1 (logic 0) or B2 (logic 1) as the

active data channel.
NC 10,11 No connection allowed

OH 12 Output On/Off hook status of POTS equipment

DTMF_RDY 13 Output Signal to inform controller a DTMF tone has been detected

RING_EN 14 Input Control to cycle on and off theRING voltage when DC_EN is

active.

DC_EN 15 Input Control signal to enable 150 VDC generation for RING signal.

This pin should be held high from before the first RING ENable

until the phone set goes off hook or the caller hangs up.

PWR_CTRL 16 Input Control signal for powering up POTS telephone set.

ROUTE_CTRL 17 Input Control pin for voice signal switching inside the module.

/PDI 18 Input Power down mode control.

D4 - D7 19-22 Output Connect to controller main data bus low byte, lines D4 - D7;

carries DTMF code.

-12V 23 -12V DC power supply

GND 24,28,45,47 Ground

+12V 25 +12V DC power supply

Mu/A 27 Input Connect to logic 1 (+5V) selects A law and logic 0 (GND) selects

Mu law

B_M_CLK

/RCLK

(IDL/GCI)

46 When this pin is held at a logic 1, FST, BCLKT, DT and DR

become IDL mode. When this pin is held at a logic 0, FST,

BCLKT, DT and DR become GCI mode.

VCC 48 +5V DC power supply

Page 4 XEISDNP

Electrical Specifications

ABSOLUTE MAXIMUM RATINGS

Parameter Maximum Value*

Supply Voltage VCC (+5V) +6.5 Volts

Supply Voltage VDD (+12V) +15 Volts

Supply Voltage VEE (-12V) -15 Volts

DC input voltage (TTL inputs) -0.6 Volts to +6.5 Volts

Storage Temperature Range -25C to +85C

Lead Temperature (soldering, 2 sec/wave) +260C

Operating Temperature Range 0 to 70C

*Exceeding these values may result in permanent damage to the device

POWER SUPPLY CHARACTERISTICS (Ta = +70C)

Symbol Parameter Min Typ Max Unit Notes

VCC Supply Voltage 4.75 5.0 5.25 Volts

ICC VCC Supply Current 10 mA

VDD Supply Voltage +9 +12 +15 Volts

IDD VDD Supply Current 100 mA

VEE Supply Voltage -9 -12 -15 Volts

IEE VEE Supply Current 20 mA

I/O Characteristics

ANALOG TELEPHONE PORT (POTS) SPECIFICATIONS

DC Supply

20 - 24 Volts nominal

Ring Voltage

60 VAC nominal

Voice Transmission

Frequency range: 300–3000 Hz
Impedance: 600 ohms (nominal)

Signals Provided

Supervisory: dial tone, busy tone & ringback

Signals Decoded

Dialing: DTMF and dial pulse

XEISDNP Page 5

Application Circuit

Page 6 XEISDNP

Central Office Function

The XEISDNP Analog Phone Line Adapter provides an interface between an ISDN Terminal
Adapter data channel and an analog (POTS) telephone. In an analog (Plain Old Telephone Service)
system the Central Office (CO) of the telephone company supplies a customer telephone with DC
power when the subscriber handset is removed from the hook (off-hook) and delivers calling progress
tones, like Dial tone, Ring-back signal and Busy signal when the phone is in use. In addition, when a
call arrives while the handset is on-hook, the CO sends an AC signal to ring the phone set. The CO
detects and digitizes the key tones or dial pulses and the subscriber’s voice signals for transmission
through the network.

ISDN provides a pure digital service to the subscriber, with no provision for line power or analog
signaling tones. Therefore to use analog equipment with ISDN service these functions must be
provided locally. The XEISDNP is designed to duplicate the analog user front end (line card) of a
Central Office switch. The following list summarizes the CO functions which the Adapter must replace:

• Sending ring signal to an on-hook phone when its number is called.

• Sending supply power to the telephone set when it is off-hook.

• Sending calling progress tones, including dial tone, busy signal and ring-back tone.

• Detecting and encoding the tones generated when the user “dials” a number.

• Coding the local users voice signal for the digital system and decoding the incoming digitized voice

data to an analog signal for the local hand-set.

Adapter Functional Blocks

CODEC

The CODEC inside the XEISDNP converts the voice signal from the telephone handset to a digital
data stream and sends it to the ISDN Terminal Adapter. From the other direction it receives the
processed B channel bit stream from the Terminal Adapter, converts it to analog voice signal, then
sends it to the telephone handset. The coding/decoding scheme may be changed from A-law to Mu­law by switching the pin 27 Mu/A setting. The communication between the CODEC and the ISDN
controller uses either GCI( also known as IOM-2) or IDL standard depending on the logic level of pin

46. The data channel can be set for B1 or B2 of the ISDN line by the logic state of pin 9.

DTMF Decoder

The “touch tone” keys on a phone set generate Dual Tone Multi-Frequency (DTMF) tones. In a
POTS system, the DTMF tones are detected by the central office system, but in ISDN service, the
Terminal Adapter provides this function. The decoding inside the XEISDNP module converts the tones
to a digital signal the main ISDN controller (XEISDNU, for example) can read. It also generates a
DTMF_RDY signal to inform the controller a DTMF tone has been detected. The main controller then
issues a DTMF_EN signal to enable the DTMF code output to the system data bus. The four-bit DTMF
code is placed in the low byte of the data bus in the high nibble of the byte (D4 - D7).

Ring Signal Generation

An analog phone requires a 60_90VAC ring signal, so a voltage inverter has been designed inside
the module to convert the +12 volt power input into a high voltage ring supply output. Pin 3 is for
testing this voltage and should be bypassed to ground with a 10uF/250V capacitor. When DC_EN (pin

15) is pulled high by the TA Module, DC_OUT (pin 3) should have a 150_170 VDC output. The input
signal to control the ring active period is RING_EN (pin 14), which can be controlled by the TA Module
to cycle the ring signal (pin 2) in a pattern of two-seconds active or four-seconds active. (See Figure 1
on page 7)

XEISDNP Page 7

Figure 1. Ring signal control sequence and Timing

Handset Power

Whenever the phone set connected to the POTS module is off-hook, the module will feed the phone
set with a DC current, normally in the range of 30 to 50 MA. At the same time it sends an off-hook
signal through the OH pin (12) and keeps it high until the local phone set hangs up.

Configuration and Setup

When the XEISDNP is used with the XEISDNU Terminal Adapter in the recommended application
circuit, all setup and configuration is controlled by the Terminal Adapter.

DC_EN

RING_EN

RING_DC

5VDC
5VDC
150VDC

60-90VAC

RING

Page 8 XEISDNP

Terms of Sale

Devices sold by XECOM are covered by the warranty provisions appearing in its Terms of Sale
only. XECOM makes no warranty, express, statutory, implied, or by description regarding the
information set forth herein, or regarding the freedom of the described devices from patent
infringement. XECOM makes no warranty of merchantability or fitness for any purposes. XECOM
reserves the right to discontinue production and change specifications and prices at any time and
without notice. This product is intended for use in normal commercial applications. Applications
requiring extended temperature range, unusual environmental requirements, or high reliability
applications, such as military, medical life-support or life-sustaining equipment, are specifically not
recommended without additional processing and authorization by XECOM for such application.

Life Support Policy

XECOM assumes no responsibility for the use of any circuitry other than circuitry embodied in a
XECOM product. No other circuits, patents, or licenses are implied. XECOM’s products are not
authorized for use as Critical Components in Life Support Devices or Systems.

Life Support Devices or Systems are devices or systems which, (a) are intended for surgical
implant into the body, or (b) support or sustain life, and whose failure to perform, when properly
used in accordance with instructions provided in the labeling, can be reasonably expected to result
in significant injury to the user.

A Critical Component is any component of a life support device or system whose failure to perform
can be reasonably expected to cause failure of the life support device or system, or to affect its
safety or effectiveness.

Copyright, XECOM © 1997

While Xecom, Inc. has made every effort to ensure that the information presented here is accurate,
XECOM will not be liable for any damages arising from errors or omission of fact. XECOM reserves
the right to modify specifications and/or prices without notice. Products mentioned herein are used for
identification purposes only and may be trademarks and/or registered trademarks of their respective
companies.

Xecom, Inc.

374 Turquoise Street

Milpitas, CA 95035 USA

Tel: 408 • 945 • 6640

Fax: 408 • 942 • 1346

www.xecom.com

#9708-XEISDNP