Model 100
Intro
Manuals
RAM
Serial cable
The serial port on a Model 100 is 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, 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.
The easiest cable to assemble from common parts you may already have lying around, is a common 9F/25M pin serial modem cable, combined with a 9F/9M null-modem adapter.
The perfect cable though, would be a 9F/25M null-modem cable. That configuration is unusual, but they do exist. Here are some for reference:
- This one is "perfect" in that it has the right connectors and wiring, without needing any null-modem or gender changer adapters added, and works with everything in the system rom and all normal software, including telcom, basic, and all tpdd clients.
- However one thing it does not do is rts/cts. This cable has those signals shorted to self-satisfy on both ends.
- No built-in or 3rd party software uses hardware flow control (with one exception). IE there is no way to even set hardware flow control in TELCOM or in BASIC, and no DOS clients use it because the TPDD & TPDD-2 themselves don't.
- But the hardware in the M100 CAN actually use rts/cts if you manipulate the uart yourself from a machine language program (or I suppose, peek/poke from basic). The only software I know of that does this is HTERM. So this cable is NOT good enough for HTERM.
Others, probably better, but yet to be verified if any are really "full handshake":
RAM Expansion
ROM Adapters
Pinouts
REX
FigTronix
Molex_Chip_Carrier