DG> > DG>  supra 144 with rom V1.80-05 TR14-Jxxx-001 191 
DG> but i seem to be experienceing some difficulties with this modem 
DG>  that the supra 144 LC does not exhibit . and vice verse . 
DG> i enjoy the 144 as it gets flawless CID packets 
DG>  but it seems to have an intermittent problem accepting commands . 
DG> aprox 1 in 60 commands sent to the modem will not get executed . 
DG> the command is echoed and the  at end of line also 
DG>  but the command is not executed and no response is sent back . 
DG> i wrote a little test script that sends an AT and waits for the OK .
DG>  the errors vary from 1 appart to a few hundred appart 
DG>  with the average about 1 in 60-70 will not be executed . 
DG> this happens also for other commands such as ATA or any other string
DG>. 
DG> i have tryed this also on a second 144 from a newer production run 
DG>  but with the same rom of course and got the same results . 
DG> i have managed to set up detection routines to watch for this effect
DG>  and reSend the command that does not get executed that work quite
DG>  well  but there are some situations where it is not practical . 
DG> with the LC in 10,000 attempts i got flawless results , not 1 fail .
DG>  but it seems to have trouble getting CID packs for calls that 
DG>  come in with a VERY short first ring signal from the phone company
DG>.   IE if the first ring is not the full 2 second tone but just a
DG>short blip . 
        You are talking about modems with board designs that have
        not been made in a couple of years, but my guesses are these:
        1.      The AT parse routine or the modems clock Freq. is
                just "slightly" off.
        2.      The waveform (in an ideal world the serial port
                signal goes instantly from the positive to the
                negative voltage level...in the real world this
                takes TIME) sent from your computer or the
                clock rate is slightly off.
        Both are equally possible.
-Patrick Moore
 Sysop of Supra BBS 
CMPQwk1.42 331ūSupra modems ... so strong they come in a metal box.
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