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Community Member

- Transparent CCS for Clear Channel Codec

I have a network as follows

ISDX PBX -- 3660 - 100 MB eth - 7206VXR - ISDX PBX

I am using TCCS for VOIP ( clear channel)and digital E1 modules at each router. The config works ok and all channels connect and voice is okay.

However after a few hours we see line/phase errors at the 3660 E1 controller which results in temporary channel loss as remote controller goes down.

Any suggestions as to why this is happening, the config has been checked as okay, timing ok , PBX's ok.

Cisco Employee

Re: - Transparent CCS for Clear Channel Codec

Please check the controller. If there are slips check the clock settings. If there are Line code violations, check the cabling and do a loopback test. Make sure also the parameters (crc4, ...) match the PBX ones too.

Please check this documents:

E1 Layer 1 Troubleshooting

E1 Troubleshooting

Hard Plug Loopback Tests for E1 Lines

Understanding the show controllers e1 Command

More docs about Digital CCS (PRI, BRI, Q.SIG, T-CCS) :

Community Member

Re: - Transparent CCS for Clear Channel Codec

A couple more things to check:

- Check the 100 mb connection, make sure it is HARD coded to 100 Meg, full-dux, and not set to AUTO.

- Configure the cable-length command on the T1 controller. The default is cable-length long, which inserts some padding ( + gain) into the local T1 line to accomodate a longer loop. This can overdrive a short local loop. If the router is 133 feet or less from the PBX, then use "cable-length short 133"

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