DM> It may have something to do with 2400 connects, as that is all
DM> Paragon has at this stage.

RS> OTOH it is a classic situation where flow control must be absolutely
RS> right, the phone line rate is such a long way from the rate between
RS> the PC and the modem that a blemish will show up very dramatically.
RS> Whereas for example inadequate flow control, but with the modem/PC
RS> speed not locked, but following the phone line speed, wont generally
RS> make a flow control problem visible on an upload.

DM> If it were a flow control problem, surely it would show on any
DM> transfer protocol, not just Zmodem.

No, a small block, non windowed protocol doesnt need flow control. For
example with Xmodem, the sending comms prog sends a block, small one
too, and waits for an ACK form the receiver. The block is so small that
it cant overflow the buffer in the modem, so if flow control isnt
working you wont notice since flow control wont be used anyway.

Same applys when the PC/modem speed matches the phone line speed. Even
with a protocol like Zmodem which sends forever regardless, the sending
modem never needs to tell the sending PC to stop sending because it can
squirt the stuff over the phone line as fast as it can get it from the PC.

DM> Anyhow, I uploaded a rep packet to Paragon, and the damned thing
DM> worked on Zmodem.

DM> At first thought, it could have been by modem init string, but then
DM> it comes around again, why is only Zmodem that plays up ? The othe
DM> two transfers protocols that I have tried, Sealink & Kermit, both
DM> worked fine, every time.

Yeah, rather odd. I guess it may be that Paragon just had a problem with
the setup of the Zmodem protocol driver itself.

DM> The Zmodem upload worked once or twice in both versions, and then
DM> carked it. It starts uploading, and then fails after the 1st 1k block.

RS> Very odd, particularly as you see it on other than Pauls. Paragon
RS> isnt using Spirits is it ? I've forgotten what you are using yourself.

DM> No, the upload to TML was fine using Zmodem. I'm not sure what sort
DM> of modem(s) Paragon is using, but I am beginning to shy away from
DM> them because of the lost messages. Now it looks like I may call back
DM> in to check for lost messages !

DM> I have a Maestro SE.

RS> Its possible its just finger trouble. Flow control is rather messy
RS> since it needs to be right in the comms software and the modem and
RS> there are quite a few variations on the hardware flow control in the
RS> physical modem. Then there are cable and serial port possibilitys.
RS> The combinations can bite you at times.

DM> Another furphy thrown into the equation is that I use the same
DM> version of telemate on 2 PC's, one at home & one at work; 2 different
DM> modems - a Maestro SE, & a Netcomm M4.

DM> It looks as if I will have to get serious with this & devote some
DM> time to sorting it out.

Yeah, looks like it. Wouldnt be the first time that its something caused
by a bizarre combination of things.