ben@moncol.UUCP (Bennett Broder) (09/26/89)
We recently purchased and installed a Telebit Trailblazer plus modem for the purpose of transfering news. Unfortunately, I seem to be encountering a problem getting the modem to connect reliably in "fast" mode. I have been sitting near the modem when this happens, and I can hear the following: The modem places the call (as expected), the remote modem answers (as expected), the remote modem puts out the pep answer tones (as expected), my modem ignores these tones (why?), the remote modem puts out the 1200/2400 tones (as expected), and my modem connects at 2400 baud. Other times, (calling the same site, with the same configuration) the modem connects in fast mode without a hitch. It seems to work correctly about 75% of the time and fail 25% of the time. The phone connection (through an AT&T System 85 PBX) is (at least to the naked ear) reasonably good. My news feed is getting annoyed at tying up his line on a full feed at 2400 baud. Any help would be appreciated. Ben Broder ..princeton!moncol!ben ..att!tsdiag!moncol!ben
larry@nstar.UUCP (Larry Snyder) (09/26/89)
> the pep answer tones (as expected), my modem ignores these tones (why?), > the remote modem puts out the 1200/2400 tones (as expected), and my modem > connects at 2400 baud. Other times, (calling the same site, with the > same configuration) the modem connects in fast mode without a hitch. Make sure you are programming your modem to connect in FAST mode only via the interal NRAM and not via a long command sequence. -- Larry Snyder uucp: iuvax!ndcheg!ndmath!nstar!larry The Northern Star Usenet Distribution Site Notre Dame, Indiana USA
scotto@pnet01.cts.com (Scott O'Connell) (09/27/89)
> re: modem won't connect in fast mode but does at 2400 etc.
I had the same problem here in San Diego. Worse yet it was while I was
evaluating v.32 modems. I tried them on a couple o
f lines and still the
best I could do was 2400. After many weeks of firmware changes, modem
paramaters and hours of frustration Telebit (one of the modems I was
evalMY}uating) set up a Spectrum Analyzer and found the problem. It
was easy to spot because the PEP sends out a narrow pilot tone. If there
is a loss on the line in that area the modem doesn't hear the other modem.
This was complicated by my V.32 testing which uses a much wider pilot tone.
Anyway, the phone company didn't understand the problem, said that the
line was within specs and left. I found a line that worked, had them do
a comparison and they said "No difference". Then they started swapping
pairs and discovered the problem followed a short strech of underground
cable about 5 miles from my office and 2 miles from the CO. They swapped
that section for another pair and everything is working fine.
If it hadn't been for Telebit tech support I'd have been completely
frustrated and settled for staying at 2400. I'm glad they took the time
to help out.
If anyone is interested, I have prints of the spectrum analyzer results
that Telebit did. I also would recommend talking to Lisa Masnaghetti at
Telebit and reminding her of my problem.
-- Scott O'Connell
Scott O'Connell - Datagram Corp. UUCP: {hplabs!hp-sdd sdcsvax nosc}...
3297 Sweetwater Springs Blvd #8 ...!crash!pnet01!scotto
San Diego, CA 92078-1477 ARPA: crash!pnet01!scotto@nosc.mil
800/235-5030 INET: scotto@pnet01.cts.comphilf@xymox.metaphor.com (Phil Fernandez) (09/28/89)
In article <111025@nstar.UUCP> larry@nstar.UUCP (Larry Snyder) writes: >> the pep answer tones (as expected), my modem ignores these tones (why?), >> the remote modem puts out the 1200/2400 tones (as expected), and my modem >> connects at 2400 baud. Other times, (calling the same site, with the >> same configuration) the modem connects in fast mode without a hitch. > >Make sure you are programming your modem to connect in FAST mode only >via the interal NRAM and not via a long command sequence. Wait a minute!!!! Why is this? Shouldn't S50=255 in NVRAM be *exactly* the same as S50=255 in a command sequence? phil +-----------------------------+----------------------------------------------+ | Phil Fernandez | philf@metaphor.com | | | ...!{apple|decwrl}!metaphor!philf | | Metaphor Computer Systems |"Does the body rule the mind, or does the mind| | Mountain View, CA | rule the body? I dunno..." - Morrissey | +-----------------------------+----------------------------------------------+
rd@tarpit.UUCP (Bob Thrush) (09/29/89)
In article <562@moncol.UUCP> ben@moncol.UUCP (Bennett Broder) writes: > [ about occasional slow speed uucp connections between 2 Trailblazers] Several sites in this area have experienced the same problem. The effects of the problem can be greatly reduced by 1) not locking the interface speed and 2) making the high speed getty prompt unique from the slow speed prompts. By specifically looking for the unique high speed prompt in the L.sys/Systems chat script, you can fail the occasional slow speed connection and try again on the next cron run. >Ben Broder >..princeton!moncol!ben >..att!tsdiag!moncol!ben -- Bob Thrush rd@aii.com or uunet!tarpit!rd Automation Intelligence,Inc.,1200 W. Colonial Drive, Orlando, FL 32804