Hello Pix, hello Pan!
I’m grateful to you very very much.
You are absolutely right – they use DTMF tones. And – yes, as their specialist said, that server isn’t an ordinary one (PSTN as usual) -“it’s also a modem connected to a terminal”. It’s true, we have something like MS to MS schema.
In some days I’ll be there and I’ll see this “invention” with my own eyes. I’ll try to get full description of their system (used equipment, protocols etc) in order to find answers to our questions
Thanks a lot for very useful information, I appreciate you help very much.”
P.S. This forum is excellent, I’ve got more help here than from TAC of our vendors :)))
Thanks a million