MoIP: How do we make modem calls over IP? (and general chat about phone networks and modems, T1, E1, BRI 56k etc)

[RCourtney]

Still doing testing with the Grandstream device but so far it seems consistently about 200ms WORSE than the Cisco ATA. I have both of them setup side by side on my PBX and make modem calls back to back to a BBS on a "real" landline using each ATA. The GS gives me a RTT of about 200ms higher on average.

I've poured over all the configuration options to see if there's anything I'm missing, but there are 50000 of them so it's possible I've overlooked something. I've also tried a few different firmware revisions, including the latest.

Voip.ms has two service levels "Premium" is what I use. The other thing I have tried when not NEEDING public access is IPTEL.ORG. They process the SIP setup but RTP is direct between endpoints.

 

[famicomaster2]

At ~$200 I wouldn't call that cheap. But a BBA is really nice to have for save file management to a PC over the LAN and for ripping games.

The cheapest way I found to get a 56K setup going was to get a Windows Server machine + Eicon Diva PRI + Adtran Total Access + a couple cables I had to make. Around $400 investment and a couple hours of time. I would think the ethernet adapter is by far the cheapest way to go for >33.6K on a Dreamcast.

I'm not really well versed in ISDN protocols
I suppose they only do Euro-ISDN, their BRI cards have "S0" marked on them (S/T bus).
There is also a card for T1 access, it will only work if your device can act as a TE (same goes for the E1 access card).
Do you know of any other "PBX" options with lots of BRI/FXS + a few T1/E1s other than Adtran 550/830/890s ?

S/T existed in the US, too. U loop is much more useful to me personally, though.
In the US, the most common protocols are 5ESS, DMS100, and NI1. There's a bunch in Europe which I don't know the names of off the dome.

The PBX wants to be NT on T1? That's a little unusual, but the Adtran TA924e3G running my house can act as either NT or TE selectable on all four ports.

If you intend to terminate (TE) BRIs, you can use some Cisco routers and a bunch of PBXes very successfully, but BRI was not very popular here so most of the equipment is focused on PRI and BRI stuff is hard to find. The Adtran Atlas 500 and 800 series are about the cheapest way you can get it. VConsole makes a BRI-FXS and a BRI-PRI translator box, which I want, but they are $2500 new and rarely show up used. There is at least one other translator, but I do not remember it's model name. I seem to recall they were on very similar pricing to the VConsole units.

 

[Cloudschatze]

Ah, I am not attached to SIP on my Adtran. When assigning an ISDN number plan, it applies to all active PRI NT ports. I am calling port to port on FXS, out to the PRI for the Dialfire, and I have a VoCa FXO provided by the cable company which lets me answer and originate outside calls.

Sorry, I'm just getting around to responding to this.

Calls from the FXS ports to the PRI ports should be subject to the same trunk group accept/pattern matching as SIP-based calls.

For example, if I wanted to add an additional, arbitrary extension/DID to the Patton 2800 trunk group, it would just be another pattern/rule:

voice grouped-trunk "PATTON 2800 TRUNK"
trunk T02
accept 385-596-1770 cost 0
accept 1-385-596-1770 cost 0
accept 385-867-5309 cost 0

In which case, dialing 385-867-5309 from an FXS port would connect to the 2800 via "Trunk T02," which, in my setup, is PRI 3.

It sounds like you might have all of your PRI trunks assigned to a single grouped-trunk? If so, splitting those into separate trunk groups, with separate accept/pattern matching, should get things routing the way you'd like.

Unrelated aside, but are you running the latest firmware (R14.4.2.E) on your Adtran unit, and have you had any issues with "garbled" PRI calls? I tracked this down to the clock source configuration being "corrupted" by simply viewing the T1 details in the GUI. I reported the issue on the Adtran community forum a couple months back. Here's hoping it gets addressed (assuming they're even planning another firmware release, at this point...).

 

[famicomaster2]

Sorry, I'm just getting around to responding to this.

Calls from the FXS ports to the PRI ports should be subject to the same trunk group accept/pattern matching as SIP-based calls.

For example, if I wanted to add an additional, arbitrary extension/DID to the Patton 2800 trunk group, it would just be another pattern/rule:

voice grouped-trunk "PATTON 2800 TRUNK"
trunk T02
accept 385-596-1770 cost 0
accept 1-385-596-1770 cost 0
accept 385-867-5309 cost 0

In which case, dialing 385-867-5309 from an FXS port would connect to the 2800 via "Trunk T02," which, in my setup, is PRI 3.

It sounds like you might have all of your PRI trunks assigned to a single grouped-trunk? If so, splitting those into separate trunk groups, with separate accept/pattern matching, should get things routing the way you'd like.

Is there a way to do this through the GUI? I can assign a bunch of numbers, sure, but they all point to all ports. 200-0000 and 867-5309 are both in the ISDN Number Plan section, and both will ring the Dialfire, the PortMaster, *and* my Eicon DIVAs. I can't figure out how to assign a number per-port. I want something like, 200-0001 for PRI1, 200-0002 for PRI2, etc.

I don't have SIP set up, I was attempting to get it onto the TSP network and we got as far as getting it registered, but no calls go through, incoming or outgoing. Eventually, the SIP people in the Discord gave up trying to make it work and so it sits with settings that should work but don't.

Unrelated aside, but are you running the latest firmware (R14.4.2.E) on your Adtran unit, and have you had any issues with "garbled" PRI calls? I tracked this down to the clock source configuration being "corrupted" by simply viewing the T1 details in the GUI. I reported the issue on the Adtran community forum a couple months back. Here's hoping it gets addressed (assuming they're even planning another firmware release, at this point...).

I am, and yes, I've had some unusual behavior from it before.
Distortion when calling Dialfire 2960. Went away after a restart of the Adtran

 

[maxtherabbit]

I encountered the 43.4 kbps reference in some Avaya documentation and figured it might be more generally applicable. I haven't tested it yet though, so it may very well be as much a misadventure as the higher V.90/92 rates have been.

We might be onto something here. I've been calling an ISDN BBS over SIP using my Adtran TA912 and a USR V.90 modem. If I connect at the default uncapped speed of 54.666kbps the call will never survive a retrain attempt. However by using the AT&N28 command to limit V.90 speed to 42.666kbps I find that retrains will reliably succeed. At 44kbps (AT&N29) they will succeed more often than not and the higher you go the worse it gets.

I think for MoIP using V.90 and SIP the practical speed limit is going to be 42.6k, which still offers a nice boost over 33.6k even if not realizing the theoretical capacity.

 

[Neoa_56]

I recently acquired 2 internal European I-Modems (17€ on Vinted with another modem) and a Dialogic Diva 4BRI-8 (~30€ on eBay), my wish is to integrate everything in a single computer with Asterisk and 56K/33.6K dial-up.
View attachment 1315578View attachment 1315579View attachment 1315581
It's still not clear if Digium FXS cards are capable of handling 56K, though.
There may be another solution, as there is a post of someone on Reddit (currently discussing with them) using an I-Modem as the 56K digital modem and as the TA for the analog modem, on a Digium B410P ISDN Asterisk card.
If Asterisk doesn't work, I'll just buy some cheap Siemens or Panasonic PBX, probably a KX-TDA15/30 or an HiPath 3000/5000

For K56Flex support, I may also use a Multitech ISIHP-2S / ISIHP-4S card over BRI.

 

[Neoa_56]

The cheapest way I found to get a 56K setup going was to get a Windows Server machine + Eicon Diva PRI + Adtran Total Access + a couple cables I had to make. Around $400 investment and a couple hours of time. I would think the ethernet adapter is by far the cheapest way to go for >33.6K on a Dreamcast.

Cheapest way to do that here in europe would be to get an Eicon Diva BRI and a cheap PBX that does BRI (S/T) and FXS (Panasonic TDA15/NCP500, Siemens HiPath lineup, Alcatel OmniPCX S...)

The PBX wants to be NT on T1? That's a little unusual, but the Adtran TA924e3G running my house can act as either NT or TE selectable on all four ports.

The PBX wants to be the TE, but that can be somewhat annoying when trying to connect T1/E1 modem cards directly to the PBX, as they have to support being switched to NT mode (I reversed the two in my first message, sorry).
Diva PRIs can be set as NT iirc.

 

[MiaM]

Sorry if this is a noob question and sorry if I've already brought this up, but:
Are T1/E1 equipment in general "genderless" (for a lack of a better wording) in that either end can generate or recover the clock, and either end can initiate communication and whatnot?
Or does TE mean "terminal equipment" and can you generally have PC PCI/PCIe cards acts at the opposite of TE?
(Sorry again if I've asked this before. I'm using an Ericsson Businessphone PBX (ASB 150/02) and I think I have two cards for E1, and the only testing I've done is trying to connect two of these PBXes to each other using these cards and I couldn't get anything working. It would be nice to be able to talk to the PBX via E1 with some type of PC interface card).