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Hey All,

I'm likely years late on this, but I've had an issue in my home lab that has been bothering me for a while. I have a BCM50 with DTM and have had issues with getting the PRI to work properly. There was always *something* that didn't work right, and I played with all different switch types and switch type combinations with minimal success. I ended up settling on NI-2 on the BCM and 5ESS on the Cisco 2851 (yes, I know, mixed switch types..) that acts as my TDM switch worked, but with no Calling Name Display. Ok, fine, but I was determined to make this work 100%.

I finally hunkered down and analyzed the Q.931 debug output from the Cisco. I played with different switch types and settled on NI-2 on both sides. Calls inbound to the BCM worked fine, had Calling Name display and the works. However, outbound calls from the BCM over the PRI to *any* destination could not move past ALERTING. Once CONNECT was sent, the BCM threw a fit and rejected the call. So you could ring the far side, but answering meant death to the call.

When analyzing the debug output, I realized that upon CONNECT the Cisco was sending the CONNECTED NUMBER Information Element at which point was when the BCM said NOPE. So, I modified the ISDN config for the D channel on the Cisco side to *not* send the CONNECTED NUMBER IE and, holy cow, IT WORKS BEAUTIFULLY!

Here is the config from the Cisco in case anyone is interested:

interface Serial0/1/1:23
description BCM50
no ip address
encapsulation hdlc
isdn switch-type primary-ni
isdn protocol-emulate network
isdn incoming-voice modem
isdn supp-service name calling
isdn negotiate-bchan
no isdn outgoing ie connected-number ! <-- THIS is the magic line
no cdp enable

Attached is a screen shot of the DTM config on the BCM.

You have no idea how happy I am to see this working properly 100%!!


Star for your perseverance.

Marv ccna


Thanks guys!


Another star!


Toronto, Canada

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