I am posting this here as it is a specific question but about a piece of equipment that I have no experience with. If not for that it would be in the VoIP upgrade thread.
Eventually the place I work is buying a new PBX. They are leaning toward a Mitel 3300 since our corporate HQ bought one.
The question is can the 3300 do FXO signalling on a T1 interface. I mean real FXO signalling, described elsewhere on this forum as "standard FXO using D type ABCD bit signaling on the ESF framed DSO bit stream"?
PBX towards FXS:
Idle state (No ringing)
ABCD = 0101
Ringing state
ABCD = 0000
Talk State
ABCD = 0101
FXS towads FXO:
Idle State (On Hook)
ABCD = 0101
Talk State (Off Hook)
ABCD = 1111
I have also heard this type of circuit referred to as Loop Start circuit or Line Side T1.
Back story: We currently have a perfectly good ROLM 9751. It even shows you caller ID number since two of it's T1 trunks interface with a couple of PRI T1s from the LEC through an Adtran 550. What more could these people want?
OK I'm being cheeky here, it is no longer supported by the manufacturer and the resellers will run out of parts eventually.
Back to the back story. We have hundreds of analog lines used for modems and faxes. I guess they can be made to work. :rolleyes:
We also have hundreds of FXO/FXS lines, about half of which are used for dial up modems. This is where the problem lies.
The current set up is the T1s from the ROLM are connected to a DACS and DS0s are connected to whatever DS0 they need to be. The cross connect in the DACS is groomed 0101,0101. The ROLM trunk is configured "OPX". The remote end of the DS0 is connected to a FXS channel bank card. The card is connected to a plain old telephone set. Works great for both incoming or outgoing calls. No caller ID of course but other ROLM features work fine through flash/enter code.
The comm techs at HQ tell me that the only signaling option for the Mitel T1s is off hook = 1111, on hook = 0000 with all four bits toggling for ringing. I do not know what the part number is of the T1 interfaces they are using in the Mitel. All I know at this point is that they either had to have all the FXS cards modified or replace them with 4W E&M cards and a 2W/4W hybrid.
I spoke with a Mitel sales rep when they were here to wow the IT types and he told me the type of T1 signaling I described never existed. They referred me to one of their experts who repeated the same line. He told me to do what I described there had to be channel banks with FXS cards in there somewhere.
OK, that last part was kind of a rant. I'm getting old and crabby and don't like to be told I am full of it in front of a bunch of suits and engineers.
So, Mitel techs, can it be so? Are we going to have to take all of our FXS phone circuits back to 4W E&M like in the analog days?
Dave
