Hi Thnks for the reply...So say if i want 120 channels over ss7 signalling...will the telco give me 4 E1s and 1 separate E1 for ss7 signalling or will the ss7 be in one of the 4 E1s itself..? Do i have to just plug in those 4 E1s directly into the TE420P and install libss7 ? thats it ? Also please tell me what are the advantages of ss7 over PRI in terms of 1.call handling capacity 2. connectivity 3. reliability ... Thanks Sriram -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.digium.com/pipermail/asterisk-ss7/attachments/20080813/07801ded/attachment.htm