[VoiceOps] IAM callername instead of CNAM

Paul Timmins paul at timmins.net
Wed Feb 3 11:55:45 EST 2010

This is quite possible. You could have a customer who is either sending 
the name and the carrier is translating it directly to the GenericName 
field in the ISUP, or they're sending it on a PRI in the Facilities or 
Display IE and the switch is translating it to GenericName.

Why do terminating carriers listen to the contents of the GenericName 
field, one might ask? (Shouldn't they be doing a CNAM dip 
unconditionally, after all?) Because Canadian calls implement caller ID 
with name that way. They don't use a CNAM database like we do in the US. 
If you ignore GenericName, you lose out on caller ID with name data on 
Canadian calls.


milosz wrote:
> hi all,
> has anyone heard of a US residential carrier transmitting the 
> callername parameter from the IAM instead of doing a normal CNAM 
> lookup?  i have some users--for whom the pbx is (intentionally) set up 
> to transmit an invalid cpn--who are claiming that when they call their 
> home phones from the office, their internal (sip) caller name appears 
> on the caller id along with the invalid cpn, which makes no sense from 
> a CNAM lookup standpoint.  the only thing i could think of (other than 
> they are nuts/lying) is that their gateway is transmitting the sip 
> callername in the IAM and the carrier is passing that along instead of 
> doing a lookup.  the btn is the same for all users so that can be 
> ruled out.
> they are all on cablevision or time warner.
> thanks,
> milosz
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