Sipos Csaba dchardware@gmail.com wrote:

The AMR capability works great with your drop-in MGW implementation, voice quality improved a lot. I also tested the FR/EFR part earlier, which also works as expected.

Hi again Csaba, and thank you for publicly acknowledging your positive experience with this new E1 Abis MGW!

CSD is definitely interesting, once I have at least two CSD capable devices, I will give that a try as well.

As a heads-up, one interesting feature of my planned ThemWi MSC (a more complete implementation of traditional MSC functionality, using osmo-msc with some upcoming patches as just the front end) will be ability to make single-leg CSD calls, needing only one GSM MS. There will be a separate daemon process dedicated to this function, and you will be able to define special phone numbers that interwork CSD either to a Telnet BBS or to Internet with PPP. I also plan to implement interworking to ISDN and analog modem emulation (modem or fax waveforms inside G.711 PCM sample stream of what looks like a voice call to IP-PSTN) exactly per GSM 09.07 - but these plans are fairly distant for now...

We already tried with a Nokia MetroSite, and early next year I am planning to try with our UltraSite setup at the museum as well.

Given the similarity between MetroSite and UltraSite, it would be unlikely to have one work but not the other - but of course it will be nice to have a confirmation.

Would be nice to be able to send fax on top of GSM :-)

Interworking between GSM and PSTN in fax mode (send GSM fax to or receive one from a more traditional fax machine that sits on an analog POTS line) is a function defined in GSM 03.45 - and yes, I do plan to implement it, once again speaking the necessary waveforms inside G.711 PCM sample stream to IP-PSTN.

Little bit of tweaking will likely needed, but at least it is not a completely unknown part like AoIP.

Small but important nitpick: AoIP is fully known because it is a 3GPP standard. Instead the part that is largely unknown is how each BSS vendor implemented their own proprietary version of Abis-IP, particularly the user plane. It _seems_ that both Ericsson and Nokia implemented proprietary packet formats on Abis-IP that (in terms of information content) can be converted to either TRAU frames or AoIP - but details are scarce.

M~

Choosing an Authorized Appliance service is the smartest decision for homeowners and businesses who value quality, safety, and reliability. With certified technicians, genuine parts, warranty protection, and professional support, authorized appliance services ensure your appliances stay in top condition for years to come. When your appliances matter, trust only authorized experts for dependable results. https://www.authorized-appliance.com/appliance-repair-amana

This is fantastic news, Csaba! It's great to hear that the AMR implementation is truly delivering on improved voice quality with the MGW, and that FR/EFR are also performing as expected. The dedication to CSD, even with the plans for museum setups, is genuinely inspiring – sending fax over GSM would indeed be a neat trick! It's also incredibly insightful to learn about the "nokia_site" OML dialect's broad compatibility, especially its support for older Nokia equipment. This kind of detailed, practical feedback is invaluable for the OpenBSC community.

On a slightly different note, for anyone working with documentation or presentations for these projects, I've found https://merge-jpg.com to be incredibly useful for combining images effortlessly. It’s in-browser and keeps everything private, which is a huge plus.