The initial plan
When Dukenet initially conceptualized Usenet, the planners had three things in mind.
Running UUCP called for a single dial-up modem port. The issue here was about the dialing. Someone had to make the call and pay the charges. Auto-dial modems did not exist (the Hayes Smartmodem came much later. The leased Bell autodialer was too expensive. Usenet was an unstructured project. Buying a modem was itself an issue. Paying monthly lease charges would not be workable. The solution planned was to use an acoustic coupler, which could act as the interface device. The solution was what Duke could afford.
The solution developed by the grad students worked like this:
The Dialing problem
When the dialing happened manually, this solution worked well. All that had to be done was to pick the handset, make the call, and placed the handset in the coupler. An issue remained, which was how the computer would do the dialing. The connection from the coupler to the computer happened through the RS-232 standard. The modem pins were five in number. They were ground, CD (carrier detect), transmit, receive, and DTR (Data Terminal Ready).
When the modem connected with the computer, i.e.: when the serial port was opened, the DTR signal would be sent. When the modem was connected, a ‘carrier detect’ signal would be sent. When the connection at the other end dropped, the modem then dropped CD. The signal then returned to the calling program. The solution was using a DTR signal. It helped solve Duke CS’s needs.
Duke implemented this solution successfully. Prof. Steven Bellovin of Columbia University liked the idea and thus created his variant. The following is a description of Prof. Bellovin’s variant:
Prof. Bellovin then created a driver program. The program controlled the DTR line. The driver program ensured the modem, as well as the dialer, were seen as two different devices by UUCP.
Now came the last and most serious problem, who would foot the bill? During those times phone calls were pretty expensive. Calling during normal working hours would be extremely expensive. Phone calls in the evening would cost lesser and night calls the lowest.
The solution worked out was that Duke would take the responsibility for the calls since they had the autodialer. Any site wanting to join the network had to get a modem with an auto-answer feature and pay Duke. It was decided that the system would make calls at night and keep it to not more than two times to keep expenses at a minimum.
This plan called for money to be exchanged. There would be a spike in the phone bills. Duke had to receive as well as process payments from other sites. Usenet happened because it had the official sanction. It also materialized because the faculty members valued innovations by graduate students.