Model T Serial Cable

Summary

The ideal cable to go from a PC to a Model 100, 102, 200, or 600, is "9F/25M serial null-modem full-handshake".

The serial ports on Models 100-600 are wired DTE, the same as a com port on a PC, but with a female connector, unlike any pc.

This is a backwards configuration from everything else today. There is some suggestion that maybe this is actually the original standard, and IBM came along later and changed it by putting male connectors on their PCs, but in any event, 25pin DTE ports being male has been the universal standard now for decades.

Any modem or printer or digital scale or any other kind of peripheral with a serial connection will be wired DCE with a female connector, usually 25 pin.
Any serial port card or usb serial adapter for a PC will be wired DTE with a male connector, usually 9 pin.

That means that usually you always need some kind of adapter between a PC and a M100/102/200/600.

The easiest way to connect with parts you are most likely to already have lying around, is to use a 9F/25M Modem Cable combined with a 9M/F Null-Modem Adapter.

Ideal cables

These cables are wired null-modem, have all the connections for hardware flow-control, and the right connectors on both ends, all in one factory-molded piece. You don't need any null-modem adapters or gender-changer adapters.

C2G 03019

DCD+DSR<-->DTR

S+PG

No RI

Amphenol CS-DSNL4259MF-005

DCD+DSR<-->DTR

S+PG

No RI

StarTech SCNM925FM

No DCD

No RI

Less ideal cables

These cables actually work fine for pretty much everything, including TPDD client/server connections, since there isn't even any way to *set* hardware flow control in either BASIC or TELCOM anyway.

But the hardware in Models 100-600 *can* actually do RTS/CTS, if you manipulate the UART registers yourself from a machine language program. The only software I know of that does this is HTERM. So these cables are NOT suitable for HTERM