help wrt UUCP between 3B1 OBM and TB

Greg Andrews gandrews at netcom.COM
Wed May 8 15:08:34 AEST 1991

In article <1991May5.121256.4453 at blilly.UUCP> bruce at balilly (Bruce Lilly) writes:
>This is a well-known problem with Telebit modems (at least the TB+) when
>operated with the interface speed locked. The Telebit puts out a
>non-standard signal, which causes the 3B1's built-in modem to receive
>garbage (the 3B1's OBM is rather intolerant of non-standard signals).
>Telebit refers to this bug as "bit-shaving".
>Your options are:
>1)	don't operate the Telebit's with interface speed locked
>2)	try to get Telebit to fix the problem (1-800-TEL-EBIT) (good luck)
>3)	trade in the Telebits for another brand of modem
>4)	use an external modem on the 3B1 which will accept the Telebit's
>	non-standard timing

"Good Luck" is a pretty good sentiment.  Why?  Because it's NOT a Telebit
bug.  Bruce, you can call it Telebit's "problem" and "non-standard timing"
all day long, but that's simply not the case.

As I mentioned in my other article, Stop Bit Deletion (and the corresponding
Stop Bit Insertion) are a part of the modulation spec.  The modem that can't
handle re-inserting the stop bit is the one with the problem.  Telebit modems 
can handle Stop Bit Insertion - guess which modem has the problem?

As I'm at home tonight, I can't quote chapter and verse from the specs on
this, but you can be certain that I will find it and quote it for you.  If
it turns out I'm wrong, I'll eat my words on it.

My last posting was wrong on one point:  Telebit modems perform Stop Bit
Deletion in the Bell 212 and V.22 (1200 bps) modulations also - not just
V.22bis (2400 bps).

>	Bruce Lilly	blilly!balilly!bruce at sonyd1.Broadcast.Sony.COM

 |  Greg Andrews   |       UUCP: {apple,amdahl,claris}!netcom!gandrews    |
 |                 |   Internet: gandrews at netcom.COM                      |

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