jtn@ADS.COM (John T. Nelson) (11/20/90)
Sorry if this has been posted before. We're having signficant net problems.... I'm having a problem with my Racal Vadic 9632 VP running in 9600 baud modem. Hope somebody out there knows what's going on 'cause I'm stumped. Let's look at the parameters of the modem. I'm running with Hardware Handshake turned on, 8N1, EC and MNP 5 turned on and all other parametters are standard. Sometimes I run the modem with 7 bits and 1 even parity but that doesn't seem to affect the outcome. The modem is connected to a Macintosh II cx computer and I use a shareware package called Zterm as well as the UUCP look-alike UUPC. Okay, let's look at the symptoms. First I connect to a Sun computer and a 2400 bps modem. No idea what the brand of the modem is, but at any rate I can do ZMODEM and XMODEM and UUCP with the 2400 bps modem with no loss of data. This indicates that at least the 2400 bps modem chip in my modem works properly. Then I set the speed for 9600 and try ZMODEM to the same computer but this time with a Telebit T2500 modem which should be able to talk to my 9632 VP since both talk V.32. Now here's where the fun starts. Remember, exact same settings on everything except for a higher speed. But now when I try ZMODEM transfers one of the moedms or computers chokes after the first 1024 byte packet. One packet is shipped. Then the second is begun but now Zterm claims that it has ZRPOS = some number and starts counting retries. Usually gets to about 14 retries before Zterm quits the transfer. Sometimes the transfer gets about 50% into the file. Sometimes it chokes right after the first packet. Most of the time it chokes after the first packet. Now I have hardware handshake turned on so the modems should be handshaking their packets. EC and MNP are turned on so that shouldn't be a problem right? Unless the Telebits aren't keen on EC or MNP 5. I have Trellis turned off because Telebits don't recognize Trellis. So... for some reason the modems choke on the data and I suspect its the high speed. I hope it isn't a problem with the Telebits. UUPC shows the same symptoms. The transfer succeeds for maybe 5 minutes and then at some indeterminate time, the modems stop transfering data and one of the two will sent periodic "heartbeat" pulses to the other modem as if it was waiting for some kind of acknowledgement. But it never comes. So... exact settings but different speeds sends my 9632 VP into limbo. Anybody have any ideas on this? Anybody else out there have a Macintosh connected to a 9600 V.32 modem? I'm at a loss to figure out what's going on. Thanks. -- ORGANIZATION: Advanced Decision Systems GEOGRAPHIC: Arlington, VA UUCP: kzin!speaker@mimsy.umd.edu INTERNET: jtn@potomac.ads.com SPOKEN: John T. Nelson PHONE: (703) 243-1611 PROJECT: Macintosh hacking -- "Love the Machine... Hate the Company"