CMX208 Просмотр технического описания (PDF) - CML Microsystems Plc

Номер в каталоге

Компоненты Описание

производитель

CMX208

ISDN Dual Telephony Protocol Engine

CML Microsystems Plc 

ISDN Dual Telephony Protocol Engine

CMX208

1.5 General Description

The CMX208 is a single-chip data processor which has been mask programmed with firmware to

implement an ISDN protocol stack. This enables the CMX208 to provide two analogue (POTS) ports

with an ISDN S-bus network connection. Key variables are stored in an external EEPROM and the

user can provide additional features by adding external ROM and RAM. Access to the firmware

Application Programmer's Interface (API) facilitates the seamless integration of the user's additional

features with the pre-programmed ISDN to POTS interfaces.

The CMX208 is intended for use as part of an ISDN chipset and all descriptions in this data sheet refer

to this implementation, which is shown diagrammatically in Figure 3. The use of alternative chipsets is

not supported.

The firmware supports connection to an ISDN S-bus network interface via the AMD AM79C30 ST

controller with integral PCM codec for a single POTS port. An auxiliary Motorola MC145480 PCM

codec will need to be added for the second POTS port.

The CMX208 interfaces with up to two CMX605 Tone Generator and DTMF Receiver chips, which

decode incoming DTMF tones and generate call progress signals (eg busy tone) normally originating

from an analogue telephone exchange. The firmware translates the CMX605 data into ISDN D-

channel commands and vice versa to support both incoming and outgoing calls. For the ISDN

interface, D-channel commands sufficient for standard telephony applications are implemented. With

the aid of a small amount of discrete circuitry, exchange battery voltage, ringing current, line reversal

and off-hook detection are also supported, to complete the POTS interface. The CMX208 has

dedicated outputs for visible indicators (LEDs) which can be used to provide information on the call

status. Support for Multiple Subscriber Numbering is also included in the firmware.

The CMX208 can be configured by means of keypad programming via either POTS port.

Configuration parameters allow the user to change (for example) the format and cadence of the

ringing signal, so as to facilitate use of the CMX208 in different countries. Each POTS interface is

able to configure the variables relevant to its own use.

An Application Programmer's Interface (API) is available and is described separately in section 1.5.6.

Further details are available on completion of a Non-Disclosure Agreement. Please contact CML

Sales directly for further details.

The firmware and finite state machine embedded in the CMX208 have been used in products which

have gained ETSI CTR3 approval.

© 1999 Consumer Microcircuits Limited

9

© 1999 Chiron Technology Limited

D/208/1

Share Link: