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c30050814
Beginner

Call Manager Express (CME) 10.5 - TELKOM South Africa BRI Configuration

After recently completing an installation of a CME in South Africa connecting to 3 x TELKOM BRI lines for PSTN access, I found very little helpful information online so I'm going to submit my findings.

 

I had several issues getting LAYER 1 up and running on the BRI lines, this lead me down the path of looking at cable pin out issues and I found a lot conflicting information online. I finally managed to get in contact with an ex TELKOM technician who confirmed TELKOM use pins 3,4 and 5,6 for ISDN basic rate lines. There were many other suggestions online including rollover cables, ie. All pins reversed, and also crossing pins 3,4 with 5,6. With one another stating pins 1,2, 3 and 6....

 

Please note this was interfacing with a TELKOM NT1 for ISDN2. (They also have an ISND2a iteration - this I have not tested). It turns out I had a bad batch of VIC2-2BRI-NT/TE cards (4 of them to be exact!!). Cisco TAC turned around some replacement cards and in the end it was a plain old straight through cable that brought up layer 1 on the lines.

 

Next I just wanted to confirm the switch-type and codecs I used to get the lines running correctly and produce the best results in terms of audio quality. Again none of this is documented very well for TELKOM South Africa.

 

Working configuration of BRI interfaces and voice-ports shown below:

 

interface BRI0/1/0
no ip address
isdn switch-type basic-net3
isdn point-to-point-setup
isdn incoming-voice voice
isdn sending-complete
isdn static-tei 0
trunk-group 1
!
interface BRI0/1/1
no ip address
isdn switch-type basic-net3
isdn point-to-point-setup
isdn incoming-voice voice
isdn sending-complete
isdn static-tei 0
trunk-group 1
!
interface BRI0/2/0
no ip address
isdn switch-type basic-net3
isdn point-to-point-setup
isdn incoming-voice voice
isdn sending-complete
isdn static-tei 0
trunk-group 1

voice-port 0/1/0
compand-type a-law
cptone ZA
bearer-cap Speech

voice-port 0/1/1
compand-type a-law
cptone ZA
bearer-cap Speech

voice-port 0/2/0
compand-type a-law
cptone ZA
bearer-cap Speech

 

Also strangely TELKOM didn’t present all of the digits for the ‘called’ number when the external call hit the CME. For some reason they were stripping off the leading digits and only sending the last 4 numbers. I have no idea why…. I had to correct this with a translation pattern to reach my internal extensions.

 

 

4 REPLIES 4
trevor240
Beginner

can you send a config of the translation patterns?

Sure thing. I was receiving a 90XX number. the DDI range is 9000 - 9054

 

I've translated the 90XX number I was receving from TELKOM to a 790XX number, which is our internal 5 digit extension range...

 


voice translation-rule 1
rule 1 /^90\(..\)$/ /790\1/


voice translation-profile inbound
translate called 1

 

voice-port 0/1/0
translation-profile incoming inbound

!
voice-port 0/1/1
translation-profile incoming inbound

!
voice-port 0/2/0
translation-profile incoming inbound

Can you send me the output from test voice translation-rule 1 9032

#test voice translation-rule 1 9036
Matched with rule 1

Original number: 9036 Translated number: 79036
Original number type: none Translated number type: none
Original number plan: none Translated number plan: none

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