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Lucent G3I ISDN PRI to Cisco 3660 PRI 1CT1 + MICA Modem bank problem

Symptom: T1 does not come up, no CD, local alarm on Cisco, D channel is down on Lucent box.

Configuration: isdn primary-5ess, framing, linecode, pri-group timeslots all configured. D chanel configured for encap ppp, isdn primary-5ess. Async Group created with ppp mode dedicated etc. Lines configured for dialin only.

This probably falls under the layer one rule of networking, but I suspect one (or more) of three things is wrong - 1 - a standard Telco 50 pin to DB 15 cable isn't the correct cable for this scenario (Pin 48 to Pin 1 etc). 2 - I have the wrong PRI card ( 1CT1 with 15 pin connector, but not the one with the integrated CSU) to connect to a ISDN PRI Trunk card in the Lucent. 3 - The Lucent guy needs a different PRI card in his switch. If there is anyone out there that has hooked up a Lucent G3 PRI to a 3660 PRI-1CT1 card knows if I need a special cable or something it would be appreciated!!!

This solution is to replace a bank of modems and a multi-port serial card in an NT server performing RAS.


Re: Lucent G3I ISDN PRI to Cisco 3660 PRI 1CT1 + MICA Modem bank

If "sh controller T1" shows the T1 as down, and "sh isdn stat" shows layer1 as deactivated, it likely is a physical layer issue.

1 - If you have the NM-1CT1, then you need to connect to an external CSU and the cabling should be straight through (or NULL modem if connecting directly); the pinouts are here:

It does not sound like you have an NM-1CT1-CSU.

2 - If it's a 15 pin connector then you do NOT have an internal CSU; this means you can either connect to an external CSU, or connect directly to the Lucent.

3 - I would not think the PRI card on the Lucent would effect Layer1 stuff...

New Member

Re: Lucent G3I ISDN PRI to Cisco 3660 PRI 1CT1 + MICA Modem bank

Thanks for the link. I'll have the Lucent guy get me his pinout and we'll tone out the cable between us. Darn Lucent is always doing something strange with their cables.

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