Communicating with a PC using a Sinclair computer not having a serial port can be challenging. But the TS-2068 can communicate directly with a PC modem via the TS-2050 modem to transfer text files. In the past, the procedure was to upload files to a BBS by one computer and then download with the other which was a hassle. Of course, having a serial port, communication is made with a “Null modem” (techy for a cable).
To communicate, modems have to have a line that has a tone (carrier) and that provides a ring (signal). Connecting two modems together from two computers eliminates the carrier and the signal and the modems will not recognize each other. It has been done with the two modems connected to the same phone line that held up calling or receiving phone calls for the duration. That, can be a long time at 18 text characters per second which is what I get with the 2050.
With a Hayes compatible PC modem, here is how:-
1. Connect the two modem lines that normally go to the telephone line together using a two-line plug without any connections to the telephone line.
2. Turn on both modems and load the modems software. MTERM II, Loader V or MaxCom /Xmodem for the 2068. Load buffer etc.
3. Set both computers to Terminal mode and the TS-2068 to ASCII (toggle con: none) if using MTERM II, or Xmodem. Of course, parameters such as 8N1, Xmodem etc. have to match the PC modem’s or vice versa.
4. On the PC modem, ENTER ATA (which is the Hayes command that forces the PC modem to answer the phone without the benefit of a carrier or a signal). The PC modem emanates a long squeal and recognizes the signal from the other modem and connects.
5. Set the PC to Download (Receive) mode, Xmodem or ASCII, 300 BAUD and enter the file name.
6. From the TS-2068 select SEND (Transmit) file “name.CT” and ENTER.
7. The PC acknowledges and receives the file.
8. If the PC does not recognize the end of the file, exit SEND to Terminal mode and ENTER Ctrl Z or X (SHIFT-7 Z or X) to tell the PC “End-Of-File”.