That's where the "ridiculously expensive" part kicks in: the only modems that me...

tyingq · on March 28, 2016

These $9/shipped generic USB modems worked on Linux for me: http://www.aliexpress.com/item/Adroit-New-USB-56K-V-90-V-92-...

Not great quality, but it sounds like you just want to go off hook and send a single DTMF tone. (ATH1, then ATD6). It should work fine.

chx · on March 29, 2016

Thanks! I will need to figure out how to configure mgetty to do an ATDT6 on dial.

tyingq · on March 29, 2016

Sure. Looking at mgetty's man page, it looks like you would want to

a) Disable Auto Answer on the modem, manually: ATS0=0

b) Set the "answer-chat" setting in mgetty to send the ATH1 then ATDT6

I imagine you'll also have tons of errors, since no actual modem-to-modem data connection will ever get established in this scenario. So maybe some options to suppress all that.

Kliment · on March 28, 2016

There are cheaper options, for example the Trendnet TFM-561U which claims linux support