838-Serial Adapter
This DB25‑to‑DB25 serial crossover adapter allows modem‑style devices—such as the WiModem and other DCE‑type RS232 peripherals—to plug directly into the TI‑99/4A RS232/1 port with no cable modifications, rewiring, or hacking required.
The adapter uses two DB25 male connectors and preserves a straight‑through connection for all RS232 signals except one intentional crossover:
Transmit Data (TD) ↔ Receive Data (RD) are swapped between connectors.
This simple crossover aligns the TI‑99/4A’s DTE transmit/receive lines with modem‑class devices, eliminating the need to cut, splice, or repin cables just to achieve proper communication. All other RS232 signals—including RTS, CTS, DSR, DTR, and carrier detect—remain straight‑through for full compatibility with software expecting standard handshake behavior.
The result is a clean, reliable, cable‑free solution for connecting modern or legacy serial modem devices directly to the TI‑99/4A Peripheral Expansion Box RS232/1 port—no custom cables, no guesswork, no hacks.
- Availability: 7 In Stock
- Model: 838-SerialAdapter
- Brand: 838 Designs