Weird adapter

[Joe E.]

I came across this adapter in our "junk" closet (photos in the attached pdf). There are no markings inside or out. Nobody in the plant knows what it's for. One end is a standard DE-9M, the other is a standard DB-25M. There is a short cable coming out of the side of the shell with a double-ended pass-thru PS2 connector on the end. Inside the back-shell is a manufactured PCB, with SMT components on both sides. The largest device is a quad flat-pack CPLD. Only two wires from the PS2 cable are connected, so we suspect that it's drawing power from the PS2 port to operate whatever is inside the device. Has anyone here seen anything like this? WeirdAdapter.pdf

[DanW]

Pure speculation: I seem to remember a bar code reader with a PS-2 connector that would be used in conjunction with a PS-2 keyboard for text entry. I wonder if the adapter isn't some sort of serial sniffer that was used to grab text from a serial line and feed it into a PS-2 keyboard port as though it were data entry. One side could have been the serial port of a telephone modem (DB25), the other a PC serial port (except the recent convention has had male DB-9's for the serial port and that's gender mismatch with the adapter). Edited March 2, 2013 by DanW

[Crossbow]

Might be an RS232 to RS422/RS485 converter, and may be drawing power from the PS/2 port.

[Joe E.]

My first thought was some sort of port sniffer, but it only uses 2 wires of the PS2. From a connector standpoint, it will plug directly into a "standard" DB-25 parallel port and present to the user a "standard" serial port (to the extent that serial ports were ever "standard"). Could that be what it is?

[DanW]

DB-25's were used for both parallel ports and for serial ports. I don't recall whether one or other tended to a specific gender. Telephone modems used DB-25s.

[Joe E.]

My laptop came with a port extender that has (among others) a DB-25F for a parallel port. This adapter plugs directly into it. I haven't tried it yet with the port extender actually attached to the laptop...

[RussB]

The 25 pin serial port on a PC was a male, the parallel port was female. Yes, I looked it up my memory is not that good. :)

[Steve Bailey]

Parallel to serial printer converter?

[panic mode]

time to take a look inside ;)

[Joe E.]

Already did once. I'll open it up again and post pictures.

[Joe E.]

Here's an updated pdf, with pictures of the guts. WeirdAdapter.pdf

[panic mode]

the ISPLS101x is a cPLD so it can do many things but the SJA1000 is a CAN controller.

[Joe E.]

Interesting. As far as I know, there is nothing in the plant that uses CAN.