[VoIP] In-Band Signaling

[Shane Young]

Quoting Greg Blakely <greg at vyger.net>:

> I stumbled across an odd thing today while going through the trunk
> groups that attach to the Siemens EWSD switch that I work on in my real
> life --  a trunk group that goes to the MPLSMNDT12T toll tandem, and
> it's set up for MF.
>
> I was pretty busy, but I'm almost certain that we don't actually have a
> **live** MF trunk group going to Qwest, but it'd sure be cool if we did.
> The portal number I have listed on ckts.info is served by the EWSD, so,
> if I can get the MF trunks turned up without the need of a service
> order, we may have some 'production' inband signaling for all of us to
> listen to.
>
> Probably not, though.  But, you never know

I'm pretty sure you won't be able to tell the difference.  A call  
placed either way on that trunk shouldn't have audio until the MF  
spill is done.  Even if it were an old FGC/CAMA signalled trunk, the  
audio wouldn't generally cut through until after the ANI spill is  
done.  Addtionally, because these are on a T1, they are essentially  
4-wire trunks with seperate transmit and receive paths.

I know we still have MF trunks on our DMS500 as well.

A lot of 911 trunks were MF as well to the Minneapolis and St. Paul  
selective routers, but you don't hear any MF on those either.

All of Wawina's inbound and outbound traffic is still MF, even after  
we removed the N2 carrier.  We no-longer hear the ANI.  I suspect,  
again, because it's really functioning as a 4-wire circuit.


--Shane
+1-821-7311 CNET