T1 Channel Bank

[jhaukka]

Hello. I have a client with a Carrier Access Corp. T1 Voice multiplexer that is unable to receive ESF frames. My first question is how to change from SF to ESF? The Framing Led is blinking red, the Status light is yellow and the T1 light is green. The phone company said they see nothing but errors all over the place after sending a test signal. I can't see any switches on the front side panel except the tiny dip switches up top. I think the unit is damaged because there should be 4 larger switches on the front panel but all I see is 4 empty holes. The unit has a built in CSU but my question is this. Where is the output of the unit supposed to be going? I can't tell where it goes, looks like nowhere. I'm not familiar with this type of problem and would also like to know from where the channel bank receives the clock.Is it from the incoming T1 signal? Any help at all would really be appreciated. Thanks

[bmeinck]

Question. When you say the phone company is getting errors. Are they testing from their smart jack with a T-berd (or at the switch) or are they trying to loop your CSU.

[jhaukka]

I think it was a diagnostic Bit Error Rate Test. It seems to me the CSU can't synchronize with the framing format of the T1. There is also an extended demarc on the top floor of the building they're in and I'm wondering if this could be a contributing factor? Thanks for your help,

Regards

Jyri Haukka

[bmeinck]

Well I am no expert. However, I would recommend the following. I would like the LEC to verify that they have end to end connectivity between their smart jack and the CO (other side). They can send different framing formats and test it at their level. Often times I have exp framing mismatches on the Telco's part. Now you talk about the extended demarc. I assume the CSU is there. It should not make a difference. The clocking should be external so you should not have to do anything with the csu in that regard. As far as configuring the csu for esf, maybe you can check with the manufacturer as to how to change the configuration. I can't tell you the number of times that my equipment has been blamed for connectivity issues and at the end of the day it turned out to be the carrier. Good luck!