Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!usc!apple!netcomsv!gandrews
From: gandrews@netcom.COM (Greg Andrews)
Newsgroups: comp.dcom.modems
Subject: PEP turnaround time (was Re: V.32 vs Telebit: Which should I buy?)
Summary: Far shorter than one second.
Message-ID: <1991May22.002144.2198@netcom.COM>
Date: 22 May 91 00:21:44 GMT
References: <9105210700.AA14518@ucbvax.Berkeley.EDU>
Organization: Netcom - Online Communication Services  UNIX System {408 241-9760 guest}
Lines: 28

In article <9105210700.AA14518@ucbvax.Berkeley.EDU> petty@ralvm31.vnet.ibm.com ("Jack Petty") writes:
>
>Have I read that for the Telebit proprietary modulation scheme it takes
>about 1 second to turn the line around?
>

Yes, somebody said that on the net.  Note that they are using the modems in
the USSR, where phone lines aren't very good.  His observations, while
probably accurate for his line conditions are FAR from typical.

Over clean lines the typical single-character turnaround time of PEP is
around 140-160 milliseconds.  Impaired lines will increase that time,
and certain adjustments to the modem's S120 register can have a severe 
impact on the single-character turnaround time.  That's one of the reasons
the S120 register remains undocumented - trouble calls to tech support
would triple as users twiddled the register unnecessarily, causing slow
typing and file transfer throughput.

Caveat net.user:  Lots of info on the net is accurate and useful, but not
all of it.

>Jack Petty

-- 
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 |  Greg Andrews   |       UUCP: {apple,amdahl,claris}!netcom!gandrews    |
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