Re: Interfacing to parallel port dongle via USB adapter

My experience with parallel port dongles suggests you don't have a show using
USB.

The dongles I have examined use a "stimulus/response" exchange between the
dongle and the software package without activating the strobe line so the
outboard device (printer, whatever) does not "see" the exchange as it only
latches the byte data when the strobe is activated. By that means the dongle is
notionally invisible (or really transparent?) to the printer. (Sometimes you
can daisy-chain dongles, sometimes you can't).

Unless you can - as JT indicated - capture that exchange and somehow replicate
the response to the software then you are SOL. Without being USB-familiar at
the raw signal level I can't say it can't be done, but I'd be extremely
surprised if it can.

Possibly a parallel port PCI card might work. I produce hardware that
interfaces to parallel ports for bidirectional transfer, but I haven't yet
checked out how truly those cards emulate a real parallel port.
.

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