There's a constant noise for data after the connection has been negotiated. I'm not sure how loud it would have to be to work. I do remember hooking up two mo

There's a constant noise for data after the connection has been negotiated. I'm not sure how loud it would have to be to work. I do remember hooking up two modems directly with a phone line, turning off dial tone detection on the answering modem and issuing an ATA on the answering modem and a ATDT on the calling modem and negotiating a connection that way. It still was only able to transmit at roughly 3 KB/sec.