I am looking for a technical documentation on the connection procedure used on the old Dial Up modem that generate this sound: http://www.youtube.com/watch?v=iHW1ho8L7V8
I can’t find anything on Google about this, do you know where can I find documentation about this ?
Sure it’s a little bit useless today, but I often think of “What is it doing with this noise ? What is transmitted ?”
Thank you
What you’re listening to is the analog negotiation of various features between two modems. Those of us of a certain age can identify baud rate from just the noise, even 15 years after we stopped regular usage of the things. Ahem. What I can’t tell you off the top of my head are the protocol versions.
Wikipedia has a nice list of these, as they evolved a LOT over the years. 100-baud is a very different critter than the 56K we had when dialup died.
http://en.wikipedia.org/wiki/ITU-T_V-Series_Recommendations
And if you really do want the technical definitions for all of this, the ITU still has these published:
http://www.itu.int/rec/T-REC-V/en
There were a few other protocols in use in line negotiations, but I’ve lost my modem manuals a move or two ago and can’t look them up. Digging around I find a familiar friend, MNP as well as a host of vendor-specific protocols that never took off very far.
Check more discussion of this question.