Mystery cable

[sgoosen]

I have a 6ft DB9F/DB9M cable that I'm trying to identify. On one connector it says:

    CPU
SM-SER-02A
   Rev. 1

The pinout is:

2-2
3-3
5-5

The rest don't connect to anything.

Anyone have any idea what this might be for?

Thanks,
Sam

[noname]

I think it's a simple Serial cable with no flow control: just TX, RX and GND pins are used.
It's a straight cable (TX-TX, RX-RX) so it could be used to connect a computer to a simple peripheral (modem-like).

[mastallama]

Yeah, sounds like a "null modem cable"

[dennislv]

Thats a very basic serial cable, not a null modem cable.  It's good for low speeds, as it doesn't provide hardware flow control (rts/cts) but can be used with software flow (xon/xoff)