When the operator came on the line, I’d ask her to call me back at the phone number for the modem at the computer terminal I was using. The computer terminals in the lab at that time did not have internal modems. Instead, to make a modem connection, you had to place the telephone handset into an adjacent acoustic coupler, which sent signals from the modem into the telephone handset and out over the phone lines. When the operator called back on the modem telephone, I’d answer the call and ask her to dial a phone number for me.