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From: bourman@hpcc01.HP.COM (Bob Bourman)
Newsgroups: comp.dcom.modems
Subject: Re: CODEX  V.32bis  Modems:  Experiences?
Message-ID: <820012@hpcc01.HP.COM>
Date: 18 Apr 91 16:28:51 GMT
References: <1991Feb25.122859.26635@europa.asd.contel.com>
Organization: HP Corp Computing & Services
Lines: 68

/ hpcc01:comp.dcom.modems / thad@public.BTR.COM (Thaddeus P. Floryan) /  3:57 am  Feb 26, 1991 /
In article <1991Feb25.122859.26635@europa.asd.contel.com> enger@seka.scc.com writes:
#>Folks:
#>
#>Does anyone have any experience with the CODEX V.32bis modem?
#>Anything (good or bad) to report?  Anything at all?

#One site (BIG; one of the world's largest mfrs of test equipment and computers
#located in Palo Alto CA) that has to callback my site due to security has a
#large number of the latest CODEX modems (with MNP 5 even), and the highest
#speed at which we can connect is 2400 baud.

#This is ridiculous, since my site has Telebit T2500, Digicom 9624LE, and
#other, modems with which I have NO problems calling other sites successfully
#at 9600 and 19200 baud.

#Unless that site has incompetently mis-configured their CODEX modems ('tis
#possible :-), based on my experience in this regards I would never under any
#circumstances buy a CODEX product.

#I've offered to go to that site and help them out, but they won't even lend
#me their CODEX manuals; the model number is, I believe, 2264 (or something
#like that).  If ANYONE has managed to call a T2500 or 9624LE from a CODEX
#at 9600, I would be greatly appreciative knowing HOW you did it so I can
#relay the info to the "troublesome" site.

#Thad Floryan [ thad@btr.com (OR) {decwrl, mips, fernwood}!btr!thad ]
----------


	Thad, the Digicom is an AMD chip based modem and the Telebit is
	also a propretary chip set/scheme.  Just like the USR HST modems
	you will not always get a good V.32 connection with a Rockwell or
	Motorolla chip based V.32 modem.  Most propetary scheme modems
	will try to sync up in their own mode first and then fall back
	to the V.32 handshake.  There is a problem with this.  The t1
	timer in most modems defaults to .3, .8, or 1.6 sec for the V.32
	hand shake.  You need to increase this to the max time of 3 sec.
	to give the modem time to connect. In the case of dialback, you hane
	two ways to configure the line cards. One will make the dialback
	system wait for answer tone before switching the phone line
	to the modem. This can cause the answering modem to time out on
	the the V.32 handshake and fall back to V.22bis. If you configure
	the dialback system to switch to the modem as soon as the last
	digit is dialed (early ring up) the modem will be ready
	when the answering modem (home) picks up the line and will hear
	the V.32 handshake. You my have to configure the propretary modem
	to ignore PEP or shorten the PEP protocol handshake time period
	(I'm not familiar with the T1500 or T2500) and increase the T1
	timer to 3sec. If the dialback system is set for Answer (a/a1)
	wake-up, then the connected dial back modem must wake up in
	originate mode or YOU have to answer in quiet mode (originate ATR).
	If the dialback system is configured for MI/MIC then the originating
	modem will wake up in originate mode and you can use auto answer
	mode on your home modem (ATS0=1).  

	Don't know if this helps....  I have seen problems with the TB and
	USR modems connecting to standard V.32 modems before.  I try to 
	stay away from propretary modem schemes. I don't like Rockwell
	or AMD either.... I guess that leaves DSP....... 

	Some modems have a problem with V.32 retrain. They drop carrier
	during the retrain sequence, thus dropping the line. This was/is
	the problem with the Rockwell chip set.

	Blab, Blab, Blab.... I'm out of here.....    8*)

	BOBB