Serial and Parallel Interface Cards

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RS-232 Serial Interface

This card provides the TI-99/4A with two RS-232C serial ports (also known as V24 ports in Europe) and a single parallel port. The card has a set of internal wire straps that can be changed to change the address of the card and allow a second RS-232 card to be inserted into the PEB. Ports on the card with the modified address are accessed as RS-232/3, RS-232/4, and PIO/2. The DSR on this card can be modified to make it compatible with the TI-99/8.

Atronic RS-232 Serial Interface

The picture shows the case and the PCB of the Atronic RS232 interface card.

Atronic rs232.jpg
Atronic rs case.jpg

CorComp RS-232 Serial Interface


Myarc RS-232 Serial Interface


TI Workshop Wiesbaden Serial/Parallel Interface Card

Tiw rs232 pcb.jpg

The interface card from TIW contained a parallel interface for attaching a Centronics printer, and two serial ports. In addition, it had circuitry for single-step debugging.

The card was designed and built by three people:

  • Michael Becker from the system 99 user-group (SNUG) did the hardware-design and the PAL-programming
  • Horst Wiese from TIW did the layout and
  • Juergen Stelter from TIW had assembled them all.

It is a clone of the Corcomp card, but with a PAL for decoding and some buffer chip to save the rare and expensive TMS9901 PIO-chip, which is almost always blown in defective CC-cards. The DSR is still the same as for the CC. It is a very rare item; possibly because of quality problems with the pcb only a few were built.