First post, by Cosmic
- Rank
- Member
Hi everyone,
I'm working on a FIC VA-503+ SS7 board but I can't get the serial ports working. Up until the Pentium era there was a different pinout for on-board serial, and for some reason FIC kept this older pinout for this board. Some old forum posts mention this:
Make absolutely sure that you are using the ribbon cables provided with the motherboard. Store bought, or cables from another m/b will not work with the 503. -M1pilot, 07-31-2000
A normal motherboard serial pinout:
1 2 3 4 5
6 7 8 9
The FIC 503+ pinout:
1 3 5 7 9
2 4 6 8
More info: https://www.vogonswiki.com/index.php/Serial_port
Basically, FIC kept a standard pinout on the motherboard, then the header cable was expected to rearrange the pins to match common serial cables. Which is fine, I just need to rewire my header cable.
But before getting that far I cannot get either port to pass a loopback test. I took some spare header cables and shorted two together, then connected them to pins 2 and 3 on the board. Pins 2 and 3 are always RX and TX under RS-232 and by shorting them together you should be able to see any characters typed locally, like a local echo.
However, with 2 and 3 shorted, there's no echo on Windows 98 (PuTTY, Tera Term, HyperTerminal) or OpenBSD (cu -l /dev/cua00) on either port. Both OSs see the ports and assign them an IRQ and they appear to be working normally. I triple checked the ports are enabled in the BIOS and unplugged everything except for an AGP graphics card. There aren't any IRQ conflicts and I reset the BIOS to defaults.
Does anyone have any ideas to get the ports working?