Re: Linux/PPC: RS232 with new PowerBook.
On Tue, Jun 06, 2000 at 07:12:50PM +1000, Brendan J Simon wrote:
> I have been made aware of a product from www.keyspan.com which has 2
> mini-din8 connectors on it. An Apple reseller told me about it and I
> assume it is a USB based device. I can't remember the mini-din8
> electrical specs but I don't think they have true RS232 signal levels
> (ie. +/-12volt). I think they might have TTL levels (0/5volt) but none
> the less I'm sure that an ordinary serial cable from mini-din8 to DB9
> will work, though I would prefer a similar unit with true RS232 i/o using
> DB9 (or DB25) connectors.
> Anyone know how I would use such a device from a Linux/PPC powerbook ?
> Would I need a new kernel and/or have to write my own drivers for it ?
The keyspan device works quite well under MacOS. Drivers would have to be
writen for it to work under Linux. It would probably take some work
negotiating with Keyspan, since the device requires a firmware download
before it can be used.
The device is RS-422 with outputs of +/- 5 volts. This should work with
almost all devices.
I have considered reverse engineering the protocol, but we would still need
permission to get the firmware.
The author of the keyspan single adaptor has begun producing their own
firmware. The single adaptor does not have flow control lines from what I
understand.
Since the device is composed of off the shelf components, it would
definately be possible to create our own firmware for it as well.
Dave Brown
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