PX-8 TO COMMODORE 128 CONNECTION An article by Dennis Vipond and Ron Foreman in the PX Dock describes one method of interfacing the PX-8 to the Commodore 128. It requires building an interface from scratch. An alternative method is presented here for those of you who either already own a RS 232C adapter for the C128 or who do not want to build a complete interface. I use my PX-8 mainly as a portable word processor, taking it with me on the job. Files written in the portable were essentially worthless unless they could be transferred to the "main" computer, the C128, which has a disk, printer, and real monitor attached. Since my efforts to interface the two machines concerned only the transfer of text files, I did not worry about program transfers and the required error checking protocols. Nevertheless, I believe this interfacing method can, with suitable software, be used to transfer program files. Since the C128, like its predecesors the C64 and Vic 20, does not have a true RS 232 port, some C128 owners, wishing to connect their machine to modems or other RS 232 compatible devices, have purchased commercial adapters. I found a relatively inexpensive one from Peak Peripherals, Inc. (see below). I purchased from Jameco Electronics a cable (see below) for connecting the PX-8 to a RS 232C device. It has a DIN type plug on the computer end and a male DB25 connector on the other. Unfortunately, the wiring of this cable was not agreeable to the Peak Peripherals adapter in the C128. Also, both the Jameco cable and the Peak adapter terminate in male DB25 connectors. The solution was to rewire the Jameco cable and install a female DB25 connector on it. Cut off the original male DB25 connector, strip the wires, and solder on a new female DB25 plug as follows: SIGNAL DIN PLUG DB25 WIRE COLOR --------------------------------------- Ground 1 7 green TxD 2 3 red RxD 3 2 black 4 not used CTS 5 21 yellow 6 not used 7 not used DCD 8 4 white When completed, install the hood over the DB25 plug, connect it to the Peak adapter and fire up both machines. Since we are transferring text files, I have used TERM on the PX-8. On the C128 I have used a couple different terminal programs successfully, among them Bob's Term Pro and Pro128term V.16.1 Most terminal programs should work ok. I configured TERM on the PX-8 as follows: Baud rate - 2400 Data bits - 8 Stop bits - 1 Parity -none The terminal program on the C128 is set up to match these parameters. The PX-8 can go faster than 2400 baud, but the C128, with the software I used, could not. The buffer in Pro 128term will not operate at 2400 baud, so you must "down shift" to 1200 baud if you want to capture to or send from the buffer. Experiment with the different modes of TERM. Using the above mentioned C128 terminal programs, I used mode #2; this deletes line feeds after the carriage return when sending and inserts a line feed on receive. So far, this set up has worked well. If you have any questions, feel free to write or drop a line on Compuserve. Jon Baker 440 Addison Elmhurst, IL 60126 Compuserve 72267,543 PARTS LIST - PART NUMBER SOURCE PRICE --------------------------------------------------------------------- C128 RS232 Interface na Supra Corporation $16.00 PX-8 cable APCZ Jameco Electronics 9.95 Female DB25 conector DB25S Jameco Electronics 79 or 276-1548 Radio Shack 2.99 DB25 hood DE9H Jameco Electronics .45 or 276-1549 Radio Shack 1.99 SOURCES - Supra Corporation Sells the Peak Peripherals RS232 interface 1133 Commercial Way for the C128 Albany, OR 97321 Jameco Electronics Sells the PX-8 cable and other parts 1355 Shoreway Road Belmont, CA 94002 (415) 592-8097