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ali nasser

Caller ID from PSTN---cisco----nortel


I have cisco cluster version 8.0 intgrated with nortel PBX here is the call flow .

Telco E1 -------cisco router H323--------callmanager-----router MGCP (PRI)--------nortel---- set

the caller ID from the PSTN is not showing in nortel sets.

Please advise.


Ali Nasser

Marwan ALshawi

is it showing in the CM side ?

can you debug the MGCP router and see if you sending the Caller ID

if all the above are yes then check the Nortel Pri side if dose accept it and dose not block it


1- when a call is comming from PSTN and going to Cisco extension then the calling number is showing.

2- when a call is comming from PSTN and goinmg to Nortel extension then the calling number is not showing

3- when a call is comming from PSTN and going to Cisco extension after that the user transfer the call to Nortel extension then the calling number is showing correctly

note that in the three tests the PRI links on the VG is MGCP. we did debugs on the MGCP gateway (debug isdn q931 and debug mgcp inout). from the output it is showing that the calling number is sent through the PRI link but the debug from Nortel side does not show that it is received. the debug output is attached (calling number is 90555767324 and called Nortel set is 3038)

the serial interface for the PRI link is configured as below:

interface Serial0/0/0:15
no ip address
encapsulation hdlc
no logging event link-status
isdn switch-type primary-qsig
isdn incoming-voice voice
isdn supp-service name calling
isdn bind-l3 ccm-manager
no cdp enable

For testing we converted the gateway (PRI links) in H323 and test a call direct from PSTN to Nortel set and the calling number was showing correctly. We have to use MGCP instead of H323 for some other limitation.

please advice if we can modify any parameter to enable the calling number in MGCP


Ali Nasser

hi Ali

in the isdn setup we are sending caller id with i =  0x7A83

when you decode the i value via q931 rfc :

Ext    type of number    Numbering Plan Identification          ext                Presentation-indicator         Spare             Screening

0        111                              1010                              1           00 (Presentation allowed)           000                11

we are sending the number with the needed i value for nortel to display .



Hi Haitham,

thanks for the reply. Do you mean that the issue is from Nortel side? if yes why the calling number is displayed if the gateway is H323 and not displaying if it is MGCP?

note that the calling number is also displayed if the call is transfered from cisco to nortel phone (in MGCP case)


Ali Nasser

it looks like somthing mismathing between both sides

canmake sure in the callmanager side under the MGCP GW setting the show calling number/ID set to allowed not to default  then save and reset

and try it

H323 and MGCP wont differ in this case (it will if you connect to Nortel through fxs/fxo as the caller id won’t work on MGCP as its not supported ) .

Just to double check , Can you send me the isdn q931 debugs for both MGCP and h323 ?



Frequent Contributor

When you call the Nortel internally - does the number appear?

Check the CLS of the Nortel TNB`s -

CNDA    Call Party Name Display Allowed

CNID    Call Number Information Denied

DDGA    DN Display on other set Allowed

DNDA    Dialed Name Display Allowed

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