01-05-2010 10:07 AM - edited 03-17-2019 09:54 PM
Hi I am reading a cisco book right now and I have a little question regarding a PRI.
in the book it says :
"when using T1 interfaces, channel 23 (time-slot 24) is always the signaling channel. "
So I guess Channels start from 0 to 23 and time-slot 1 to 24 ? is that right ?
also If I do a "show voice port summary" I guess the Port 0/0/0:23 is the Chnnel-D. Channel #23 wich is the times slot 24 but there is no sens if the row CH is the Channel, there would be a sens if CH would be for Times-slot because we can see that CH 23 can be used as voice port
Can some one give me a track on that...
controller T1 0/0/0
framing esf
linecode b8zs
cablelength short 133
pri-group timeslots 1-24
2811-RTR#sh voice port summary
IN OUT
PORT CH SIG-TYPE ADMIN OPER STATUS STATUS EC
============== == ============ ===== ==== ======== ======== ==
0/0/0:23 01 isdn-voice up dorm none none y
0/0/0:23 02 isdn-voice up dorm none none y
0/0/0:23 03 isdn-voice up dorm none none y
0/0/0:23 04 isdn-voice up dorm none none y
0/0/0:23 05 isdn-voice up dorm none none y
0/0/0:23 06 isdn-voice up dorm none none y
0/0/0:23 07 isdn-voice up dorm none none y
0/0/0:23 08 isdn-voice up dorm none none y
0/0/0:23 09 isdn-voice up dorm none none y
0/0/0:23 10 isdn-voice up dorm none none y
0/0/0:23 11 isdn-voice up dorm none none y
0/0/0:23 12 isdn-voice up dorm none none y
0/0/0:23 13 isdn-voice up dorm none none y
0/0/0:23 14 isdn-voice up dorm none none y
0/0/0:23 15 isdn-voice up dorm none none y
0/0/0:23 16 isdn-voice up dorm none none y
0/0/0:23 17 isdn-voice up dorm none none y
0/0/0:23 18 isdn-voice up dorm none none y
0/0/0:23 19 isdn-voice up dorm none none y
0/0/0:23 20 isdn-voice up dorm none none y
0/0/0:23 21 isdn-voice up dorm none none y
0/0/0:23 22 isdn-voice up dorm none none y
0/0/0:23 23 isdn-voice up dorm none none y
01-27-2010 12:03 AM
Cisco use x/y:23 (T1), or x/y:15 (T1), or x/y:D (AS5xxx) to indicate a PRI voice or data port.
That's all.
02-10-2014 12:47 PM
The question is, why are there 23 channels, where channel 0 should be?... it would make sense if those were TS because of TS 24 is used for signaling.
02-12-2014 12:04 PM
+5 Paolo
Gary I take it as you're curious as to how Cisco references channels and time slots. The "CH" are the 23 "B Channels"
Regards,
Yosh
02-12-2014 12:13 PM
Thank you... It makes sense, but I still confused because of this:
http://www.aculab.com/questions/how-many-voice-channels-does-a-t1-primary-rate-interface-pri-have/
Channel 0-22 - B-Channel (Voice)
Channel 23 - D-Channel (Signalling)
channel 23 is a D-Channel so it shouldn't be shown on the output.
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