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E1/T1 ISDN PRI-GROUP TIMESLOTs

Hello Guys, 

I've been configuring some E1 (ISDN PRI)  with some information I got from the Internet, but I'm a little confused about selecting the PRI GROUP timeslots.

As fas as I know, an E1 has 32 timeslots (0 to 31). TS0 is used for framing and TS16 is used for signalling (ISDN Signalling goes here). Voice channels goes from TS1 to TS15 and from TS17 to TS31.

The thing is, when you configure the controller I've seen configurations that use "pri-group timeslots 1-30" but I've also seen some others that use "pri-group timeslots 1-31". In any case, the system generates a serial interface on channel 15 wich is the one that is actually used for configuring signalling, encapsulation type.. (serial0/0:15, for example)

When using the pri-group timeslot command, does the 1-30 refers to the time slots 1 to 30 or is it referred to that there are 30 channels no matter the timeslot? 

the interface serial0/0:15 means that the TS15 is used for signalling? shouldn't be TS16?.  I guess the notation starts from 0 to 31 so that means that 15 is the TS16, but in that case, the pri group should not be always from 1 to 31 and not to 30?

I´m a little confused here...

 

  • IP Telephony
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1 REPLY
Cisco Employee

Already replied here, and yes

Already replied here, and yes, it's 0 to 31, not 1 to 32.

If you saw 1-31, they might have been using NFAS

https://supportforums.cisco.com/discussion/12138106/e1-pri-group-timeslots#comment-9561476

HTH

java

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