RS485 -> RS232 -> V34 -> RS232 -> RS485

Hmm.. interesting, my hunch (from field experience) is it would work. But I'm not sure. Maybe the first and last bytes gets corrupted. Anyone knows for sure?

Ah, but the modems are on a private line and dial/answer regardless of data being present...

Interestingly, if I interface to the RS232 at L2, I have to right bit shift and then negate the data for it to look similar to what originates at L1...

So yes, it looks like the mismatches may be cancelling each other out.

I'd best fix that then ... since I need to tap off the RS232 data at L2.

Locations are (very) remote and outside so thought I'd better check before sending someone into the wind + rain to open the cabinets and swap both sets of wires.

I guess this depends both upon the size of your arse and the vigour with which you scratch it...

Hi,

I would expect, that it won't work, because the Modem needs to be configured to dial... and with the wrong polarity of signals most modems wouldn't understand, what you want.

Marte

My arse is itchy, if I scratch it will it stop itching?

Hello,

This depends on the modem and its settings. If the modem is set up for example with error correction, it will look at the asynchronous RS232 charcater framing (start bit, stop bit) which is not valid any more if you change polarity. In this case you won´t get the correct data on the other end. If the modem uses a direct mode without any data framing (=it directly modulates the data bit by bit) it will work. Unfortulately the other case is the most usual.

Tom

only if you are using synchronous modems.

if using asynchronous modems (eg, common consumer modems) the mis-match will garble the data. because the start bit won't look like a start bit. and an idle period will look like a break.

you may get good data some of the time (data dependant) if using async modems that run the same DCE and line bitrates but modems with any sort of compression, bit-rate conversion, or error correction will probably garble your bitstream beyond recognition. (in consumer async modems this essentially rules out anything on the consumer market capable of faster than 9600bits per second, and a good number of 1200 and 2400 capable modems,

If you only send odd (or is it even?) bytes it could also work - atleast in the middle of the packets. ends could still be garbled.

Bye. Jasen

On Mon, 14 Nov 2005 03:17:03 GMT, Gunner Asch wrote in Msg.

Sou you admit to the restraint being unlawful?

robert