hooking up HP-IL with a Thinkjet 2225D RS-232 printer

[Rob Lilley]

I was wondering if a cable exists to connect a HP 71B with HP-IL to a Thinkjet 2225D printer that uses serial RS-232 interface. If a cable does not exist, is there a wiring schemematic available to interface HP-IL with RS-232. I have a NOS Thinkjet 2225D new in the box I'd love to use to print out my HP 71B programs. Thanks for your time -=Rob=-

[Raymond Del Tondo]

Hello,

you will need the HP 82164A HP-IL/RS232 serial interface or a compatible device.

HTH

Raymond

[deleted]

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[Garth Wilson]

There's also the FSI164A from Firmware Specialists, Inc. which is virtually 100% compatible with the HP82164A interface converter but has some additional nice features like larger buffers, two to eight channels instead of one, and possible battery operation.

There are others here who know the insides of HPIL far better than I; but since they have not jumped in yet, I will make a few comments. Not only is the signaling method different and incompatible, but HPIL is an extremely intelligent interface with a very sophisticated protocol, unlike RS-232 which, although it is still a good workhorse in industry even now 4 decades after its beginnings, is only a couple of small steps above dumb shift registers. The HPIL spec is very involved and is well beyond what a hobbyist can do with a microcontroller or a few logic ICs. HP used to sell kits with the custom ICs and pulse transformers and special connectors, but their nimwitt marketing people made some poor decisions and discontinued HPIL about 15 years ago.

HPIL is basically a serial implementation of IEEE-488 (HPIB) although it can iterface to a lot more devices at once. I have the 82169 HPIL-to-HPIB interface converter and have used it for controlling a lot of laboratory instrumentation with my HP-41 and HP-71, using the same HPIB commands that HP's desktop controllers used. It was mostly transparent, making it look like the IEEE-488 equipment was on the interface loop itself except that HPIL's autoaddressing could not be used on IEEE-488.

Anyway, it is definitely not the kind of thing where you can just make up a connector to interface to an RS-232 printer.