Ref: 11640124
Title: EC/1 Fails Test #13
Date: 9/4/90

Copyright 3Com Corporation, 1991.  All rights reserved.

The EC/1, now obsolete, was the precursor to the EC/2.  The EC/1 "Combo"
consists of two boards:

   * ETI (Ethernet Transceiver Interface), which resides in Slot A
     of the Series/1 Multibus backplane

   * ESB (Ethernet Shared Buffer) which resides in Slot B

EC/1 Test #13 is a loopback of a short packet with good CRC and is the
first test requiring the ESB board to communicate with the ETI board.
The EC/1 will normally fail Test #13 if connected via an 802.3 AUI Cable
or connected to an 802.3 Transceiver.  Swapping either the ETI or ESB boards
will usually not alleviate the test failure unless an Ethernet version 1 or
2 transceiver cable and transceiver are used.

If this failure is observed, it is a good idea to upgrade to an EC/2.
Further information on the EC/1 can be found in Appendix A of the Series/1
Installation Guides (09-0022-05 dated 11/86 and earlier versions of this
manual).

