Check out what Warren Zatwarniski wrote on 16 Feb 97  13:42:21:
 > Do you think it's the serial port or the modem itself? I have a
 > SupraFax 28.8 which has been flash upgraded to 33.6, and I get pitiful
 > transfer speeds if I get a 33.6 connect. I think it's a problem with
 > the modem, because if it's the serial port, should the hardware flow
 > control not take care of it? 
possibly could be the fault of the modem.
 > There was a magazine review where they tested a number of various 33.6
 > modems. The SupraExpress 33.6 modem was about 1000 cps BEHIND all
 > other modems. 
I saw the same review :)
 > I have my port locked at 115200 and I never notice any problems,
 > _until_ I get a 33.6 connect. Perhaps I'm wrong, but I think that
 > *ALL* data, regardless of the connect speed, is flowing to and from
 > the modem at 115200bps. The fact that the DCE speed is 33.6 should not
 > have any effect on the speed that the information is hitting the DTE
 > at. 
same exactly my problem (almost) I also have my port locked at 115200, and a 
33.6 connect just gives me grief (dropped carrier, hung carrier...) what you 
are saying makes alot of sense, I'm not a real technical guru or anything, 
but how much of a buffer do the supra modems have, say you lock your port at 
19200 (I have tried this and it make no difference) and you connect at 33.6 
the data is flowing to the modem and it should buffer it to send it slower to 
the computer, or does it send a stop signal to the remote host so that you 
computer can catch up (is this what RTS/CTS is all about?) I guess if the 
modem buffers the data it has to have a big buffer or else it will pile up 
and cause problems.
 > I suppose I could build a loop-back plug and check to make sure that
 > nothing's lost at 115.2, but it already hands that port speed fine.
 > I'm 99.9% positive that it's the modem which can't handle the 33.6
 > speeds, not the serial port. 
I too am beginning to suspect this also may be the case with my modem, cause 
I can connect at 28.8 (port speed 115200) with no problems, but 33.6 and even 
31.2 I pull my hair out (regardless of the port speed).
 > I'd like to hear from anyone with a supraFax.. (or maybe a suprasonic)
 > who can tell me they get good transfers (cps) during a 33.6 connect.
 > If the speeds are good (3800cps) tell me what ATI7 reports from your
 > modem. 
when I can connect at 31.2 I have seen transfers of 3300cps on rare 
ocassions, but on the internet everything tends to be slow :)
 > I have a feeling that it was purely a "fluke" that some of the 28.8
 > modems were able to "handle" 33.6 speeds. I say handle, because maybe
 > they can make a 33.6 connect, but they sure can't handle 33.6 speeds.
 > 31.2 is fine.... and I think that's pushing the limits of the
 > datapump. If you get good 33.6 transfers... I'd be curious in knowing
 > if your datapump is a newer revision than others.
this could be a very possible situation, and I also beleive the supraExpress 
33.6 ( thats what I have) are just a supraExpress 28.8 made to 'look' and 
'feel' like a 33.6).  I'll do an ATI7 and see what it gives me:
--- DLG Pro v1.0/DLGMail v2.52
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