Datasheet CMX208S1 Datasheet (MX COM Inc)

CMX208

COMMUNICATION ICs

DATA BULLETIN

ISDN Dual Telephony

Protocol Engine

Advance Information

Features Applications

•

Supports ITU Specifications

•

Supports Incoming and Outgoing Calls

•

Independent Port Configuration

•

Supports CTR3 Approval

Full API Available

•

S/T Interface

CMX208

Parallel BUS

AM79C30

S/T BUS

Controller

+ Codec

1

IOM2 BUS

CLI

DTMF Rx

CMX605

•

Feature Phones

•

Pay-Phones

•

PABX Telephones

Reference Designs Available

•

Motorola

MC145480

PCM Codec

A

S
L

I

C

B

POTS 2

A

DTMF Rx

CMX605

CLI

S
L

POTS 1

I

C

B

The CMX208 is an ISDN telephony protocol engine which implements the lower level ISDN interface and
communicates with the CMX605 and other standard devices to form a fully integrated ISDN chipset for voice
communications. The CMX208 puts all the main data processing elements in a single device. No ISDN
software has to be written and simple ‘Plug and Play’ design results. This reduces development time and
provides a highly cost-effective hardware solution. By using proven circuit designs, the designer can move
quickly from initial concept through design in to manufacture.

The CMX208 supports two voice ports over the ISDN Line, which can be used to provide ISDN telephony
services or POTS line interfaces, and has independent keypad-configuration of these services for each port.
The CMX208’s feature set and architecture allow most analog systems to be converted to an ISDN equivalent
with enhanced features.

The CMX208 is designed to work with the AMD 79C30 S/T bus interface, the Siemens PSB-21525 HDLC
formatter, the Motorola MC145480 PCM codec and the MX-COM CMX605 POTS interface circuit, and also
comes complete with embedded applications software. To support the CMX208, MX-COM can also provide
licensed reference designs on user request. A flexible Applications Program Interface (API) allows users to
customize the features and operation of their own design. The CMX208 is available in an 80-pin QFP
(CMX208S1) package.

1

The CMX208 is a data processor integrated circuit that supports the protocol layers 1, 2 and 3 of the ISDN protocol stack in accordance
with the specifications of CCITT (now ITU). These specifications, which are widely used around the world, might not be supported withi n
the U.S.

MX-COM, Inc 2000 MX-COM, Inc.
4800 Bethania Station Road, Winston-Salem, NC, 27105-1201, USA Doc. # 20480214.001
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ISDN Dual Telephony Protocol Engine 2 CMX208 Advance Information

CONTENTS

Section Page

1. Block Diagram................................................................................................................3

2. Signal List.......................................................................................................................4

3. External Components....................................................................................................7

4. General Description.......................................................................................................8

4.1 Glossary............................................................................................................................... 9

4.2 Initialization ........................................................................................................................ 10

4.3 ISDN Interface.................................................................................................................... 10

4.3.1 Activation..............................................................................................................................10

4.3.2 De-activation or Line Disconnection.....................................................................................10

4.3.3 Line Failure Detection ..........................................................................................................10

4.3.4 Incoming Calls......................................................................................................................10

4.3.5 Multiple Subscriber Numbering............................................................................................11

4.3.6 Channel Mapping.................................................................................................................11

4.4 POTS Configuration........................................................................................................... 12

4.4.1 Configuration and Control via DTMF Keypad.......................................................................12

4.5 POTS Operation................................................................................................................. 13

4.5.1 Keypad Operation ................................................................................................................13

4.5.2 Incoming POTS Calls...........................................................................................................13

4.5.3 Outgoing POTS Calls...........................................................................................................13

4.5.4 Connected Calls...................................................................................................................14

4.5.5 Call Clearing.........................................................................................................................14

4.6 Application Programmer's Interface................................................................................... 14

4.7 Hardware Description......................................................................................................... 15

4.7.1 LED Status Indicators (LED1 to LED9, and ILFI).................................................................15

5. Application Notes ........................................................................................................16

5.1 General .............................................................................................................................. 16

5.2 Approvals........................................................................................................................... 16

6. Performance Specification..........................................................................................17

6.1 Electrical Performance....................................................................................................... 17

6.1.1 Absolute Maximum Ratings..................................................................................................17

6.1.2 Operating Limits...................................................................................................................17

6.1.3 Operating Characteristics.....................................................................................................18

6.2 Packaging .......................................................................................................................... 22

MX-COM, Inc. reserves the right to change specifications at any time and without notice.

MX-COM, Inc 2000 MX-COM, Inc.
4800 Bethania Station Road, Winston-Salem, NC, 27105-1201, USA Doc. # 20480214.001
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ISDN Dual Telephony Protocol Engine 3 CMX208 Advance Information

1. Block Diagram

SLIC

POTS Port 2

CMX605

DTMF Detector

and

Caller Display

LED Status

Indicators

System Memory

and NVRAM

Handler

Auxiliary

CODEC

Task Scheduler,

Memory Manager,

Timers and Task Mailing

SLIC

CMX605

DTMF Detector

and

Caller Display

LED Status

Indicators

POTS Port 1

Handler

Figure 1: Block Diagram

D-channel

Protocol

Stacks

LED Status

Indicator

ISDN

ISDN

Interface

Chip

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ISDN Dual Telephony Protocol Engine 4 CMX208 Advance Information

2. Signal List

S1 Package Signal

Pin No. Name Type

1 SCL output EEPROM - Serial Clock
2 SDA bi-directional EEPROM - Serial Data
3 ISDNRST output ISDN S-interface Chip Reset
4 N/C output Do not make any connection to this pin
5 N/C output Do not make any connection to this pin
6 N/C output Do not make any connection to this pin
7

8

RST

DV

DD1

input CMX208 Chip Reset (active low)

power

The digital positive supply rail. Levels and voltages are
dependent upon this supply. This pin should be decoupled to
DV

by a capacitor

SS

9

XTAL

output The output of the on-chip Xtal oscillator inverter

10 XTAL input The input to the oscillator inverter from the Xtal circuit

DV

11

SS1

power The digital negative supply rail (ground)

12 LED1 output POTS Port 1 Off-Hook Indicator (HK1)
13 LED2 output POTS Port 2 Off-Hook Indicator (HK2)
14 N/C output Do not make any connection to this pin
15 LED4 output POTS Port 2 Call Connected Indicator (CN2)
16 N/C output Do not make any connection to this pin
17 N/C output Do not make any connection to this pin
18 N/C output Do not make any connection to this pin
19 LED8 output ISDN Line Activated Indicator (AR)
20

ST

output Watchdog Timer Stimulus

21 LED9 output POTS Port 1 Call Connected Indicator (CN1)
22

23

WR

RD

output Memory Write Access Strobe
output Memory Read Access Strobe

24 A19 output Memory and Peripheral Address Bus
25 A18 output Memory and Peripheral Address Bus
26 A17 output Memory and Peripheral Address Bus
27 A16 output Memory and Peripheral Address Bus
28 A15 output Memory and Peripheral Address Bus
29 A14 output Memory and Peripheral Address Bus
30 A13 output Memory and Peripheral Address Bus
31 A12 output Memory and Peripheral Address Bus
32 A11 output Memory and Peripheral Address Bus
33 A10 output Memory and Peripheral Address Bus
34 A9 output Memory and Peripheral Address Bus
35 A8 output Memory and Peripheral Address Bus
36 A/D7 bi-directional Memory and Peripheral Address and Data Bus
37 A/D6 bi-directional Memory and Peripheral Address and Data Bus
38 A/D5 bi-directional Memory and Peripheral Address and Data Bus

Description

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ISDN Dual Telephony Protocol Engine 5 CMX208 Advance Information

S1 Package Signal

Description

Pin No. Name Type

39 A/D4 bi-directional Memory and Peripheral Address and Data Bus
40 A/D3 bi-directional Memory and Peripheral Address and Data Bus
41 A/D2 bi-directional Memory and Peripheral Address and Data Bus
42 A/D1 bi-directional Memory and Peripheral Address and Data Bus
43 A/D0 bi-directional Memory and Peripheral Address and Data Bus
44 ASTB output Address/Data Bus Strobe (data bus selected if low)

DV

45
46 ~ input

SS0

power The digital negative supply rail (ground)

For manufacturer's use only. Connect to DV

directly

SS

47 PSBRES output HDLC Chip Reset
48 RING2 output POTS Port 2 Ringing Generator (low when not ringing)
49

2RING

output POTS Port 2 Ringing Generator (high when not ringing)

50 API-RXD input API/RS232 Port Rx Data (inactive = high)
51 API-TXD output API/RS232 Port Tx Data (high when inactive)
52 CLIP2 output

POTS Port 2 Line Voltage Adjustment (low when sending FSK
to a Caller Display unit. If low, it makes the SLIC present a
high impedance to the POTS line)

53

B2B1/

output B-channel Select (high selects channel B1).

54 ILFI output ISDN Line Failure Indicator

DV

55

DD0

power

The digital positive supply rail. Levels and voltages are
dependent upon this supply. This pin should be decoupled to
DV

by a capacitor

SS

56 RING1 output POTS Port 1 Ringing Generator (low when not ringing)
57

1RING

58 CLIP1 output

output POTS Port 1 Ringing Generator (high when not ringing)

POTS Port 1 Line Voltage Adjustment (low when sending FSK
to a Caller Display unit. If low, it makes the SLIC present a
high impedance to the POTS line)

59 ILINE1 input

POTS Port 1 Hook Switch Status Detector
(on-hook = low)

60 ILINE2 input

POTS Port 2 Hook Switch Status Detector

(on-hook = low)
61 REPLY input CMX605 C-BUS Interface - Reply Data
62

CMD-

output CMX605 C-BUS Interface - Command Data

DATA

63 SER-CLK output CMX605 C-BUS Interface - Serial Clock

AV

64

DD

power

The positive analog supply rail. Levels and voltages are

dependent upon this supply. This pin should be decoupled to

AV

by a capacitor

SS

65
66
67

68
69

70

AV

AV
AV

AV

REF1

SS

1CS
2CS

REF2
REF3

power
power The negative analog supply rail (ground)
output CMX605 C-BUS Interface (chip select POTS Port 1)

output CMX605 C-BUS Interface (chip select POTS Port 2)
power

power

A/D Reference Voltage. Connect to AVDD directly

D/A Reference Voltage. Connect to AVDD directly

D/A Reference Voltage. Connect to AVSS directly

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ISDN Dual Telephony Protocol Engine 6 CMX208 Advance Information

S1 Package Signal

Description

Pin No. Name Type

71 NMI input

For manufacturer's use only. Connect to DV

directly

SS

72 API-INT input API Interrupt (inactive = high)
73

IRQ

input CMX605 C-BUS Interface - Interrupt (inactive = high)

74 PSBINT input HDLC Chip Interrupt
75

76

∼
∼

input
input

For manufacturer’s use only. Connect to DV

For manufacturer’s use only. Connect to DV

DD
DD

directly

directly
77 ISDNINT input ISDN S-interface Chip Interrupt
78

79

∼
∼

input

For manufacturer’s use only. Connect to DV
For manufacturer’s use only. Connect to DV

DD
DD

directly

directly
80 N/C output Do not make any connection to this pin

Table 1: Signal List

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ISDN Dual Telephony Protocol Engine 7 CMX208 Advance Information

3. External Components

V

DD

SCL

SDA

ISDNRST

N/C
N/C
N/C

RST

DV

DD1

XTAL

XTAL

DV

SS1

LED1
LED2

N/C

LED4

N/C
N/C
N/C

LED8

CS2

CS1

V

DD

SS

REF1

DD

AV

AV

AV

REPLY

SER-CLK

CMD-DATA

ILINE2
ILINE1
CLIP1

RING1
RING1
DV
ILFI
B1/B2
CLIP2
API-TXD
API-RXD
RING2
RING2
N/C
(V )
DV
ASTB
A/D0

A/D1
A/D2

SS

DD0

SS0

V

DD

V

DD

REF2

N/C

SS

SS

SS

(V )

(V )

(V )

ISDNINT

SS

SS

(V )

(V )

IRQ

API-INT

NMI

REF3

AV

AV

CMX208S1

ST

LED9

WR

RD

A19

A18

A17

A16

A15

A14

A13

A12

A11

A10

A9

A/D7

A/D6

A/D5

A/D4

A/D3

V

SS

A8

Figure 2: CMX208 Pin-Out

This product is to be used as part of a chip-set. Please refer to the Applications Section (Section 5) for

Note:

details of the recommended chip-set.

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ISDN Dual Telephony Protocol Engine 8 CMX208 Advance Information

4. 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 interface two analog (POTS) ports to 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 in Figure 3. The use of alternative chipsets is not supported.

The firmware supports connection to an ISDN S-bus
controller and 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 certain call progress signals (e.g. busy tone) normally originating from an
analog 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) that 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 4.6. Further
details are available on completion of a Non-Disclosure Agreement. Please contact MX-COM directly for
further details.

The firmware and finite state machine embedded in the CMX208 have been used in products that have
gained ETSI CTR3 approval.

network interface via the Siemens PSB21525 HDLC

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ISDN Dual Telephony Protocol Engine 9 CMX208 Advance Information

4.1 Glossary

ACCM
API
CIDCW
CLI
CRC
CTS
DCD
DDI
DTE
DTMF
DTR
HDLC
IA5
IE
ILFI
ISDN
LAPB
LAPD
LCGN
LED
LLI
MFO
MSN
NUA
NUI
PAD
PC
PCM
POTS
PPP
PVC
RI
RNR
RR
RTS
SABM
SABME
SLIC
SPM
SVC
TEI

Asynchronous Control Character Map
Application Programmer’s Interface
Caller Identification During Call Waiting
Calling Line Identification
Cyclic Redundancy Check
Clear to Send
Data Carrier Detect
Direct Dialing Inwards
Data Terminal Equipment
Dual Tone Multiple Frequency
Data Terminal Ready
High Level Data Link Control
International Alphabet No 5
Information Element
ISDN Line Failure Indicator
Integrated Services Digital Network
Link Access Procedure – Balanced
Link Access Procedure on the D-Channel
Logical Channel Group Number
Light Emitting Diode
Logical Link Identifier
Multiple Frame Operation
Multiple Subscriber Numbering
Network User Address
Network User Identification
Packet Assembler/Disassembler
Personal Computer
Pulse Code Modulation
Plain Old (Analog) Telephone Service
Point to Point Protocol
Permanent Virtual Circuit
Ring Indication
Receiver Not Ready
Receiver Ready
Ready to Send
Set Asynchronous Balanced Mode
Set Asynchronous Balanced Mode Extended
Subscriber Line Interface Circuit
Subscriber Pulse Metering
Switched Virtual Circuit
Terminal Endpoint Identifier

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ISDN Dual Telephony Protocol Engine 10 CMX208 Advance Information

4.2 Initialization

On power-up, the CMX208 assumes its default values, which are factory programmed into the firmware. It
then performs a self-test, during which all of the LED pins and the ILFI pin are held high for 3 seconds. If the
test is unsuccessful, the CMX208 remains in this condition.

If the test is successful, the CMX208 reads its preset values from the attached EEPROM and examines the
state of the ISDN link (i.e. Layer 1) before commencing normal operation. On power-up, the ISDN link is de­activated; the POTS ports are assumed to be on-hook and ringing is disabled.

4.3 ISDN Interface

Two simultaneous voice calls are possible. Incoming calls are firstly checked for other calls present, then the
MSN is checked for validity, then the channel mapping, so that responses will be handled accordingly.

When channel mapping is enabled, outgoing calls will request the channel enabled. When not enabled, a
request for any channel is made. If no free channels are available for outgoing calls, a locally generated busy
tone is returned to the analog port.

4.3.1 Activation

Activation occurs in the following circumstances:

•

The ISDN network activates.

•

The device connected to the analog port goes off hook.
The Terminal Endpoint Identifier (TEI) is negotiated. Line powering of the CMX208 is not supported.
The 'AR' indicator (LED8) toggles between high and low states when the CMX208 is powered up, and

remains constantly low once the CMX208 identifies an activated ISDN line.
ISDN line power detection is not implemented and the CMX208 will negotiate a new TEI on any new network

activation.

4.3.2 De-activation or Line Disconnection

De-activation or line disconnection causes the TEI to be removed. Upon re-connection the CMX208 will only
be re-activated and request a new TEI when one of the conditions in the above section is met.

4.3.3 Line Failure Detection

If the line failure detection parameter is enabled (via either POTS port) the CMX208 will check that Layer 2
communications are active every sample period of 30 seconds. If Layer 2 communications are not active, the
CMX208 will attempt to activate them. If they remain inactive for 2 sample periods, the line is deemed to

have failed, so then the ILFI pin is set high and RING1,

1RING , RING2 and

pins are set low. The

2RING

CMX208 continues to attempt to activate the line and if it becomes active and stays active for 2 sample
periods, then the ILFI pin is set low and RING1,

1RING , RING2 and

pins are restored to their default

2RING

settings.

4.3.4 Incoming Calls

Incoming voice calls and calls from analog lines are directed to the analog ports and all other incoming calls
are ignored.

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ISDN Dual Telephony Protocol Engine 11 CMX208 Advance Information

4.3.5 Multiple Subscriber Numbering

Multiple Subscriber Numbering (MSN) enables each POTS port of the CMX208 to have its own telephone
number. Up to 23 digits can be saved as the MSN for each port.

All incoming SETUP messages will be checked for the presence of a Called Party Number Information
Element (IE). If one is present it is compared with the saved MSN number (if present), starting with the last
digit of both numbers. Comparison continues until there are no more numbers in the MSN saved number or
the incoming Called Party Number or there is a difference between the numbers. The MSN is said to match if
the saved MSN and the incoming calls’ Called Party Number are the same for the duration of the shorter
number (i.e. if the digit ‘1’ is saved and the received Called Party Number is 654321, then the MSN matches).
If there is no saved MSN, the Called Party Number is ignored and call processing continues.

When there is a saved MSN and the Calling Party Number transmit is enabled, all outgoing call SETUP
messages will contain a Calling Party Number Information Element.

Note:

1. When a CMX208 with MSN saved and Calling Party Number transmit enabled is connected to some

exchanges, no dial tone is heard when going off-hook.

2. Disabling the Calling Party Number transmit will mean that the called party may not receive the Calling

Line Identification (CLI), or if they do receive a CLI it will probably be the base number and not the
number specific to the calling telephone.

4.3.6 Channel Mapping

It is possible to configure the CMX208 so that the analog ports will only originate calls to and respond to calls
from a specific ISDN B-channel. This is a useful feature if, for example, you wish to have a Hunt Group on
your ISDN line and only want one voice port to ring on an incoming call.

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ISDN Dual Telephony Protocol Engine 12 CMX208 Advance Information

4.4 POTS Configuration

4.4.1 Configuration and Control via DTMF Keypad

Configuration can be carried out at any time by causing the POTS port to go off-hook and then immediately
entering a configuration sequence of DTMF tones. The sequence signaled to the CMX208 will determine the
configuration to be performed, as shown in the following table.

Configuration

Sequence

Test watchdog

Clear MSN Clears any saved digits N/A
Save Multiple Subscriber

Number (MSN)
Clear country code Country code is set to UK by default N/A

Change country code

Clear channel mapping

Enable channel mapping

Disable Calling Party No.
transmit

Enable Calling Party No.
transmit

Disable DDI transmit

Enable DDI transmit

Disable line failure
detection

Enable line failure detection

Initialize all configurations.

$9$$

#

$02$

$90$

$90$

$93$

$93$

$94$

$94$

$95$

$95$

$96$

$96$

$97$

$97$

#

n#

#

n#

#

n#

#

1#

#

1#

#

1#

1234567890#

Of the above configurations, the following are saved on a per port basis:
MSN

Channel mapping
The rest are saved on a system-wide basis, the last details entered at either port being the configuration

saved.

Name Description Default

Puts the CMX208 into a permanent loop,
not updating the external watchdog counter,

N/A

so after 2s it should reset.

n = MSN (up to 23 digits) Clear

n = country code
0 = UK
1 = Belgium

UK

2 = Rest of Europe
Incoming calls on any channel are accepted

(provided other parameters are valid e.g.

N/A

MSN).
Where n = 1 or 2 for the appropriate

channel.

No channel

map

Outgoing call SETUP messages do not
contain any Calling Party Number

N/A

Information Elements.
Outgoing call SETUP messages contain

Calling Party Number Information Element
with number set to saved MSN (if a number

Enabled

is present).
Prevents digits being transmitted to the

POTS port upon call connection.

N/A

Upon connection of a call on POTS port 1
only, if there was a Called Party Number
Information Element present in the incoming

Disabled
call setup message, the digits are sent as
DTMF tones to the POTS port.

Once the CMX208 is de-activated it stays
de-activated until the network re-activates it

N/A

or an outgoing call needs to be made.
The CMX208 checks to see if the ISDN line

is activated and Layer 2 communications
can be made. It then sets the ILFI pin

Disabled
accordingly.

Resets all of the configuration variables
back to their default values.

N/A

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ISDN Dual Telephony Protocol Engine 13 CMX208 Advance Information

Once the ‘

$’ has been recognized, each digit pressed is then checked for validity as a configuration
sequence. If any digit pressed is not a valid configuration digit, all digits pressed so far will be transmitted to
the network in INFORMATION messages as Keypad Information Elements, until a ‘#’ is entered (with the
exception of ‘$

#’ being entered, see Keypad Operation below). If the first four digits received are a valid
configuration sequence then the configuration mode is entered. When a valid configuration has been
completed the CMX208 will send a single DTMF tone to the POTS port. If a valid configuration sequence is
received but subsequent digits are invalid, then subsequent digits entered will be ignored and two DTMF
tones will be sent to the POTS port.

If the port goes on-hook part way through configuration, it will cause any digits received so far to be ignored.
Configurations can be performed consecutively with the exception of the test function (where the attached
handset must be replaced immediately after the configuration has been audibly signaled to the POTS port).
All configurations entered will be retained after a power-down as they are stored in the external EEPROM.

4.5 POTS Operation

4.5.1 Keypad Operation

The CMX208 supports ISDN keypad messages for control of Network Supplementary services either before
or during call establishment. When dialing a number (i.e. off-hook and dial tone audible on POTS port), or if a
call has been disconnected by the network but the POTS port has not yet gone on-hook, any keypad string
entered will be sent to the network as ‘Keypad Information Elements’ within INFORMATION messages.
Keypad strings are defined as the following sequences of digits, with the exception of the configuration strings
defined in the previous section:

$...#

$

When a call is connected, pressing the recall key results in all subsequent key presses being sent to the
network as ‘Keypad Information Elements’ within INFORMATION messages, until the handset is replaced.
The tones generated by the key presses are also passed down the B-channel, so the remote user will be able
to hear them.

#...#

#...#

4.5.2 Incoming POTS Calls

An incoming POTS call is identified by the Bearer Capability Information Element of the SETUP message
being set to ‘Speech' or ‘3.1kHz Audio’. The call will be routed to either (or both) of the POTS ports which
satisfy the following three conditions:

• The port is on-hook.

• The MSN saved for the port matches the Called Number in the incoming SETUP message, or no MSN is

specified for the port, or there is no Called Number in the SETUP message. See Section 4.3.5 for details
of POTS port MSN selection.

• The ISDN B-channel on which the call is placed (as indicated in the SETUP message) is compatible with

the channel mapping configuration for the port. See Section 4.3.6 for details of POTS port channel
mapping selection.

When the call is routed to a port, the ringing signal for that port will be applied by means of the RING1 and

RING1

(or RING2 and

) pins.

2RING

The call is answered when either of the ports with ringing signal goes off-hook. The ringing signal is then
stopped and the ISDN call is connected to that port.

4.5.3 Outgoing POTS Calls

Outgoing calls are initiated when a POTS port goes off-hook. An ISDN SETUP message is sent to the
network with the Bearer Capability Information Element set to 'Speech'. The dial tone presented by the
network on that ISDN B-channel which was selected by channel mapping (See Section 4.3.6), will be routed
to the POTS port initiating the call.

When DTMF tones are received from the POTS port, they are sent to the network either as Called Party
Number or Keypad Information Elements. Keypad Information Elements are discussed in Section 4.5.1.

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ISDN Dual Telephony Protocol Engine 14 CMX208 Advance Information

Receipt of a valid DTMF tone will prompt its conversion to IA5 coded digits, as shown in the following table
(IA5 hex digits are in brackets). If the first valid digit to be received is a ‘$’ then the configuration mode is
entered and subsequent digits will be monitored and saved as indicated in Section 4.4.1. If the first tone
received is not a ‘$’ or ‘#’ (See Section 4.5.1) that digit and all subsequent digits will be passed to the network
in an INFORMATION message as a Called Party Number Information Element. Digits received before the
network has returned the SETUP ACK message are saved. Upon receipt of the SETUP ACK any saved
digits will be transmitted.

The DTMF tone mapping is as shown below:

Low Group High Group (Hz)

(Hz) 1209 1336 1477 1633

697 1 (31) 2 (32) 3 (33) A (not used)
770 4 (34) 5 (35) 6 (36) B (not used)
852 7 (37) 8 (38) 9 (39) C (not used)
941

(2A) 0 (30)

$

#

(23)

D (not used)

Once the network has indicated that the full number has been received, no further digits will be sent to the
network. All tones and announcements from the network (e.g. ringing, NU, busy etc) and audio (if the call is
connected) will be routed to the POTS port initiating the call, until that port goes on-hook.

4.5.4 Connected Calls

Once a call is connected to an analog port, whether it was incoming or outgoing, a port-specific LED indicator
pin is set high to indicate that the call is connected. See Section 4.7.1 for details of the LED indicator pins.
Once the call is disconnected, either by receipt of a DISCONNECT message from the network or an on-hook
indication, the ports’ LED indicator pin is set low.

During a call, if a Recall (i.e. a line break of appropriate length) is received from a POTS port, the CMX208
will start to look for DTMF tones received on that POTS port. Any tones received will then be sent to the
network in ISDN INFORMATION messages, as Keypad Information Elements

.

4.5.5 Call Clearing

The call is cleared either by the port going on-hook or by the ISDN network. Note that the ISDN B-channel,
which was being used, is not released until the POTS port, which was in use, has gone on-hook.

4.6 Application Programmer's Interface

Details of this will be supplied to customers under a Non-Disclosure Agreement.
The following Memory Map indicates the main code areas used on the CMX208:

Function Start Hex Address End Hex Address
Code Space
External RAM
API area
AMD79C30 ISDN Interface Chip
PSB21525 HDLC Driver Chip
Reserved

000 000 01F FFF

020 000 03F FFF
0C0 000 0EF FFF
0F0 000 0F0 0FF
0F0 100 0F0 1FF
0F0 200 0FF FFF

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ISDN Dual Telephony Protocol Engine 15 CMX208 Advance Information

4.7 Hardware Description

4.7.1 LED Status Indicators (LED1 to LED9, and ILFI)
LED1 (HK1)

LED2 (HK2)
LED4 (CN2)
LED8 (AR)
LED9 (CN1)
ILFI

The functions of the LED and ILFI indicators are set out in the table below:

Pin No. Designation POTS port 1 POTS port 2

is low when analog port 1 is off-hook, high when on-hook.
is low when analog port 2 is off-hook, high when on-hook.
is high when analog port 2 is connected to the ISDN network, low when not connected.
is pulsed high and low until the ISDN line is activated, when it remains low constantly.
is high when analog port 1 is connected to the ISDN network, low when not connected.
is high when an ISDN Link Failure is Indicated, low when the link is operational.

12 LED1
13 LED2
15 LED4
19 LED8
21 LED9
54 ILFI

ISDN Line Failure Indicator ISDN Line Failure Indicator

Off-Hook ~

~ Off-Hook
~ Call Connected

ISDN Line Activated ISDN Line Activated

Call Connected ~

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ISDN Dual Telephony Protocol Engine 16 CMX208 Advance Information

5. Application Notes

5.1 General

The CMX208 is intended for use as part of an ISDN chipset. The MX-COM recommended hardware
implementation contains the following elements (refer to Figure 3):

•

‘S’ bus interface via RJ45 socket.

•

RJ11 analog telephone sockets and analog circuitry.

•

ISDN line transformer.

•

AMD79C30 S-interface controller.

•

Auxiliary Motorola MC145480 PCM codec.

•

64K bytes external RAM.

•

16K Non-volatile memory.

•

Six processor controlled LED indicator signals.

•

HDLC drivers for the 2 ISDN B-channels, both channels can be used for data transfer.

50V

5V

IOM2
BUS

AMD AM79C30

S/T CONTROLLER & PCM CODEC

FIFO & DLC Tx DTMF,RING,TONES

DISCRETE

POTS 1 SLIC

POTS

port

HY 6281009

128K RAM

IC
BUS

C-BUS

C-BUS

DISCRETE

POTS 2 SLIC

POTS

port

5 x Interface ICs

PARALLEL BUS

MOTOROLA

MC145480

PCM CODEC

CMX605

RxDTMF

TxCLID,SPM

RING & TONES

CMX605

RxDTMF

TxCLID,SPM

RING & TONES

Figure 3: Application Block Diagram

24C16

16K EEPROM

2

CMX208
4K RAM 128K ROM
PROTOCOL ENGINE

TC 1232CO

WATCHDOG

10 x LEDS

API
port

S/T

12V

MOTOROLA
MC34063A
MC7805CT
PSU

31909x029

TRANSFORMER

5.2 Approvals

The firmware and finite state machine embedded in the CMX208 has been designed into products that have
gained ETSI CTR3 approval.

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ISDN Dual Telephony Protocol Engine 17 CMX208 Advance Information

6. Performance Specification

6.1 Electrical Performance

6.1.1 Absolute Maximum Ratings

Exceeding these maximum ratings can result in damage to the device.

Supply (AVDD - AVSS), (DV
Voltage on any pin to AVSS, DV
Current into or out of any VDD or V

DD0

- DV

SS0

SS0

or DV

pin

SS

), (DV

SS1

DD1

- DV

SS1

Current into or out of any other pin -20 10 mA

S1 Package (QFP)

Total Allowable Power Dissipation at T

AMB

= 25°C

Derating above 25°C 17 mW/°C above 25°C
Storage Temperature -55 125 °C
Operating Temperature -40 85 °C

6.1.2 Operating Limits

Correct operation of the device outside these limits is not implied.

Supply: (AVDD - AVSS), (DV
and (DV

DD1

- DV

SS1

)

DD0

- DV

SS0

),

Notes Min. Max. Units

2.7 5.5 V

Operating Temperature -40 85 °C
32 MHz Xtal Frequency Tolerance -100 100 ppm

Min. Max. Units

)

-0.3 7.0 V
V

-0.3

DD

+ 0.3

-30 100 mA

1300 mW

V

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ISDN Dual Telephony Protocol Engine 18 CMX208 Advance Information

6.1.3 Operating Characteristics

Details in this section represent design target values and are not currently guaranteed.

For the following conditions unless otherwise specified:
Xtal Frequency = 32MHz ± 100ppm, AV

DD

= DV

DD0

= DV

= 3.0V to 5.0V, T

DD1

= - 40°C to +85°C.

AMB

Notes Min. Typ. Max. Units
DC Parameters

IDD (total, operational)
IDD (total in HALT mode)
IDD (total in IDLE mode)

Digital Interface

Input logic "1" level 70%
Input logic "0" level 30%
Input leakage current (VIN = 0 to DVDD)
Output logic "1" level (lOH = 120µA)
Output logic "0" level (l
Input or Output leakage current (V

= 360µA)

OL

OUT

= VDD)

Xtal/Clock Input

'High' pulse width (t
'Low' pulse width (t

WXH

WXL

)

)
Risetime (tXR)
Falltime (tXF)
Period (t

CYK

)

1 25.0 45.0 mA
1 13.0 26.0 mA
1 12.0 mA

V

DD

V

DD

-10.0 +10.0 µA
V

DD

-1.0

−

V
400 mV
10 µA

2 10 125 ns
2 10 125 ns
2 10 ns
2 10 ns

2, 3 31.2468 31.2531 ns

Notes:

1. Not including any current drawn by external circuitry.

2. Timing for an external input to the XTAL pin.

3. A fundamental cut crystal is recommended.

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ISDN Dual Telephony Protocol Engine 19 CMX208 Advance Information

6.1.3.1 Timing Diagrams

(1) Read Operation

t

WSTH

ASTB

A8-A19

t

SAST

t

HSTLA

t

DSTID

t

DRST

A/D0-A/D7

RD

(2) Write Operation

ASTB

A8-A19

A/D0-A/D7

t

WSTH

t

SAST

t

t

DAW

DAR

t

t

DSTW

DSTR

t

HSTLA

t

DAID

t

DSTOD

t

HRA

t

DWST

t

HWA

t

DRA

t

t

HRID

HWOD

t

FRA

t

DRID

t

WRL

t

DWOD

t

SODW

WR

t

Figure 4: External Memory Access Timing

WWL

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ISDN Dual Telephony Protocol Engine 20 CMX208 Advance Information

CLOCK OUTPUTTIMING

ASTB

INTERRUPT INPUTTIMING

NMI

RESET INPUTTIMING

RST

EXTERNAL CLOCKTIMING

t

CLH

t

CLR

t

CYCL

t

WNIH

t

WRSH

t

CLL

t

CLF

t

WNIL

t

WRSL

t

WXH

XTAL

t

XR

t

CYK

Figure 5: Miscellaneous Timing

t

WXL

t

XF

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ISDN Dual Telephony Protocol Engine 21 CMX208 Advance Information

6.1.3.2 AC Timing Parameters

For the following conditions unless otherwise specified:
Xtal Frequency = 32MHz, AV

DD

= DV

DD0

= DV

= 3.0V to 5.0V, T

DD1

= - 40°C to +85°C.

AMB

6.1.3.2.1 Read/Write Operation

Where: T = t

(system clock cycle time)

CYK

a = 1 (during address wait), otherwise, 0
n = Number of wait states (n = 2)

Parameter Symbol Conditions Min. Max. Units

t

Address setup time

ASTB high-level width

Address hold time to (ASTB↓)

Address hold time (to
Delay from address to

Address float time (to

↑

RD )

↓

RD

↓

RD )

Delay from address to data input

Delay from ASTB↓ to data input

Delay from

Delay from ASTB↓ to
Data hold time (to
Delay from

Delay from

RD

low-level width

Address hold time (to
Delay from address to

↓

RD to data input

↓

RD

↑

RD )

↑

RD to address active

↑

RD to ASTB↑

↑

WR )

↓

WR

Delay from ASTB↓ to data output

Delay from
Delay from ASTB↓ to
Data setup time (to

Data hold time (to

Delay from

WR

low-level width

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↓

WR to data output

↓

WR

↑

WR )

Note 1

↑

WR )

↑

WR to ASTB↑

V

SAST

t

VDD = +5.0 V ± 10%

WSTH

t

VDD - +5.0 V ± 10%

HSTLA

t

HRA

V

t

DAR

t

FRA

t

V

DAID

t

VDD = +5.0V ± 10%

DSTID

V

t

DRID

t

DSTR

t

HRID

t

DRA

t

DRST

V

t

WRL

t

HWA

V

t

DAW

t

VDD = +5.0V ± 10%

DSTOD

t

DWOD

t

DSTW

V

t

SODW

t

HWOD

t

DWST

t

WWL

= +5.0V ± 10%

DD

(0.5 + a) T - 15
(0.5 + a) T - 31

(0.5 + a) T - 17
(0.5 + a) T - 40

0.5T - 24

0.5T - 34

ns

ns

ns

ns

ns

ns

0.5T - 14 ns
= +5.0V ±10%

DD

(1 + a) T - 9
(1 + a) T - 15

ns

ns

0 ns

= +5.0V ±10%

DD

= +5.0 V ± 10%

DD

(2.5 + a + n) T - 37

(2.5 + a + n) T - 52

(2 + n) T - 40

(2 + n) T - 60

(1.5 + n) T - 50

(1.5 + n) T - 70

ns
ns

ns
ns

ns
ns

0.5T - 9 ns

0 ns
V

= +5.0 V ± 10%

DD

After program is read
After program is read

= +5.0 V ± 10%

V

DD

After data is read
After data is read

0.5T - 8

0.5T - 12

1.5T - 8

1.5T - 12

ns
ns

ns
ns

0.5T - 17 ns
= 5.0 V ± 10%

DD

(1.5 + n) T - 30
(1.5 + n) T - 40

ns

ns

0.5T - 14 ns
= +5.0V ± 10%

DD

(1 + a) T - 5
(1 + a) T - 15

0.5T + 19

ns

ns
ns

0.5T + 35

ns

0.5T - 11 ns

0.5T - 9 ns

= +5.0 V ± 10%

DD

V

= +5.0V ± 10%

DD

(1.5 + n) T - 30
(1.5 + n) T - 40

0.5T - 5

0.5T - 25

ns

ns

ns

ns

0.5T - 12 ns

VDD = +5.0V ± 10%

(1.5 + n) T - 30
(1.5 + n) T - 40

ns

ns

ISDN Dual Telephony Protocol Engine 22 CMX208 Advance Information

Note 1:

Hold time includes the time during which V

OH1

and V

are held under the load conditions of

OL1

CL = 50 pF and RL = 4.7 kΩ.

6.1.3.2.2 Miscellaneous timing

Where: T = t

(system clock cycle time)

CYK

a = 1 (during address wait), otherwise, 0.
n = Number of wait states (n = 2)

Parameter Symbol Conditions Min. Max. Units

t

ASTB cycle time
ASTB low-level width

ASTB high-level width

ASTB rise time

ASTB fall time

NMI low-level width
NMI high-level width

RST low-level width
RST high-level width

CYCL

t

V

CLL

t

V

CLH

t

V

CLR

t

V

CLF

t

WNIL

t

WNIH

t

WRSL

t

WRSH

nT ns

DD

DD

DD

DD

10 µs
10 µs
10 µs

10 µs

= +5.0 V ± 10%

= +5.0 V ± 10%

= +5.0 V ± 10%

= +5.0 V ± 10%

- 10

0.5 t

CYCL

- 20

0.5 t

CYCL

- 10

0.5 t

CYCL

- 20

0.5 t

CYCL

10

10

ns

ns

ns

ns
ns

20

ns
ns

20

ns

6.2 Packaging

Figure 6: 80-pin QFP Mechanical Outline:

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Order as part no. CMX208S1