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Layer 1 and 2 errors on ISDN2e

I have a 1760-V, version 12.2(8)YJ, with a dual NT/TE BRI VIC. I am attempting to connect the BRI ports to two ISDN2e ports from British Telecom. This is to provide PSTN access for a call manager network.

When I connect the BRI ports to the ISDN2e sockets with normal CAT5 cables, the green lights on the sockets change from flashing green to solid green. However, an 'show isdn status' still says that layer one is deactivated. If I then make a call from a 7960 handset, when 'debug isdn q921' is on, I see:

*Mar 1 00:41:53.631: ISDN **ERROR**: Module-lif Function-LIF_AddTimer Error-Unknown Class.

*Mar 1 00:41:53.631: ISDN **ERROR**: Module-lif Function-LIF_AddTimer Error-Unknown Class.

*Mar 1 00:41:53.631: ISDN **ERROR**: Module-lif Function-LIF_AddTimer Error-Unknown Class.

*Mar 1 00:41:55.638: ISDN **ERROR**: LIF_RemoveTimer Timer class 1 UNKNOWN

*Mar 1 00:41:55.638: ISDN **ERROR**: LIF_RemoveTimer Timer class 1 UNKNOWN

*Mar 1 00:41:55.638: ISDN **ERROR**: LIF_RemoveTimer Timer class 1 UNKNOWN

The 'debug isdn q921' shows no other output. The 'show isdn status' briefly turns to:

Layer 1 Status:

ACTIVATING

Layer 2 Status:

TEI = 255, Ces = 1, SAPI = 0, State = ESTABLISH_AWAITING_TEI

Before returning to:

Layer 1 Status:

DEACTIVATED

Layer 2 Status:

Layer 2 NOT Activated

To further complicate matters, I have an ISDN tester, which can connect to the ISDN2e sockets, and can make and receive calls with no problem. However, when I connect the tester (configured as NT) to the 1760 (using a crossed cable), it has the following behaviour:

- To start with, neither the tester nor the 1760 show layer one 1.

- If I make a call from the tester to the 1760, the tester shows layer 1 going up, and it stays up after the call has ended. However, the 1760 does not see layer 1 go up at all.

- If I make a call from the VOIP network to the tester, the 1760 sees layer one go up, and stay up after the call has finished, but the tester does not see layer 1 at all.

- When calling to the tester, a 'debug isdn q921' shows the same errors as above, plus it transmits several IDREQ messages. It does no receive any reply from the tester.

At no time in any of the tests do any lights go on on the BRI VIC.

The configuration of the interfaces are:

interface BRI2/0

no ip address

isdn switch-type basic-net3

isdn incoming-voice voice

!

interface BRI2/1

no ip address

isdn switch-type basic-net3

isdn incoming-voice voice

!

Two PRI ports on the same 1760 are working correctly.

Would anyone have a working cable pinout and configuration for connecting Cisco BRI ports to BT ISDN2e?

1 REPLY
Cisco Employee

Re: Layer 1 and 2 errors on ISDN2e

Hi,

Here is the url you are looking for:

http://www.cisco.com/warp/public/788/signalling/bri_voice_port_cfg.html

hope it helps,

Chinh

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