CMX208S1 MX-COM, Inc., CMX208S1 Datasheet - Page 10

• Manufacturer Part Number: CMX208S1
• Description: ISDN dual telephony protocol engine
• Manufacturer: MX-COM, Inc.

ISDN Dual Telephony Protocol Engine
4.2
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 de-
activated; the POTS ports are assumed to be on-hook and ringing is disabled.
4.3
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 occurs in the following circumstances:
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 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
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,
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,
settings.
4.3.4
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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The ISDN network activates.
The device connected to the analog port goes off hook.
Initialization
ISDN Interface
Activation
De-activation or Line Disconnection
Line Failure Detection
Incoming Calls
RING , RING2 and
1
10
RING , RING2 and
1
RING pins are restored to their default
2
RING pins are set low. The
2
2000 Chiron Technology Limited
CMX208 Advance Information
Doc. # 20480214.001
2000 MX-COM, Inc.