Discussion List for Freenum/ITAD Subscriber Number (ISN) Project

[John Todd <>]

On Oct 27, 2009, at 5:44 PM, Rick van Rein wrote:

> Hi Pete,
>
> > You can dial 0*739 to get my recording and an echo test.  Bandwidth  
> > is
> > probably not that great today, but you should at least get some  
> > jittery
> > audio :)
>
> Thanks -- although I got no audio yet, the call did come through now,
> and so it proves my code pretty much correct :-)
>
> You did raise something that I yet have to find out -- namely, if the
> local part of an ISN can start with 0.  The code I sent assumed not.
>
>
> Thanks,
> -Rick

  The preference is that ISNs local portions do not start with 0,  
since starting with zero makes it EXTREMELY difficult for dialplan  
authors to determine number prefix dialing.

  The suggested prefix for ISN dialing for North American locations  
is "012" (to compliment the "011" that is familiar for international  
dialing.)  In many other locations, "off-campus" or "international"  
dialing starts with "00".  If your ISN local component starts with  
"0", dialplans become very hairy for others to try to determine what  
type of number is being dialed on a phone that is not a SIP client  
that presents the entire sequence in one long INVITE.  (Think of  
analog phones connected to ancient switches that happen to have a  
clever SIP box somewhere in the network - every keystroke moves the  
call forward, and it's not a full dialed string that is typically  
managed.)

  So the recommended ("SHOULD") method would be to not start local  
number portions with zeros, but it is not prohibited.

JT