/edu/ - Education

Here’s the breakdown for using a 1960s-style acoustic coupler with a BBS today:

Rule number one is POTS Line Needed. Your coupler needs a real analog POTS line. Modern “phone jacks” in homes often run VoIP, which almost always breaks acoustic couplers because of digital compression and latency. If you can get a genuine POTS line (some rural telcos still offer them, or you could use an old FXS adapter with analog output), it can work.


Couplers maxed out around 300 baud (maybe 1200 with later models). That’s extremely slow: transferring a 1 MB file could take hours, so keep your expectations realistic. Most classic BBS content (text messages, ANSI art, small files) works fine at these speeds.

Acoustic couplers don’t dial automatically. You have to pick up the handset, dial the BBS number manually and place the handset on the coupler. Some couplers eventually had “automatic dialing units,” but that’s extra hardware.

Most BBS software from the late 70s–80s assumes a serial modem. You’ll need a terminal program on your “modem” side (the computer feeding the acoustic coupler) and a BBS running on a line that’s active and accepting analog connections.

If you have a vintage computer and coupler: connect coupler to handset, pick up, dial, place handset and configure terminal program for 300 baud, 8N1 (8 data bits, no parity, 1 stop bit). On the BBS side, a POTS line with a real serial modem listens for connections.