Path: utzoo!attcan!uunet!cs.utexas.edu!news-server.csri.toronto.edu!utgpu!watserv1!nbirkman
From: nbirkman@watserv1.waterloo.edu (Nancy Birkmann - DCS)
Newsgroups: comp.dcom.lans
Subject: SQE test on transceivers
Keywords: "enable or disable"
Message-ID: <1990Oct3.191251.26769@watserv1.waterloo.edu>
Date: 3 Oct 90 19:12:51 GMT
Distribution: na
Organization: University of Waterloo
Lines: 24


IEEE 802.3 transceivers generate a signal known as
Signal Quality Error Test (SQE).  Ethernet V2.0
transceivers generate a similar signal known as
Collision Presence Test or "heartbeat" and confirms that
the collision detect circuitry in the transceiver
is operating.

I  read a statement that the SQE signal is not allowed for
transceivers that connect to 802.3 repeaters.
Why?

Also, many transceiver manufacturers (e.g. Allied
Telesis, Cabletron, Interlan...) provide an option of
either providing this signal or turning it off.
Under what circumstances should the signal be turned off?

That is about all the information I have.

Most of the transceivers in our system to date have been
Digital H4000s where these options were not available.

Any information on this subject would be appreciated.