Ref: 99980138
Title: T1MMON PROMs Rev. 02A
Date: 11/5/87

Copyright 3Com Corporation, 1991.  All rights reserved.

Enclosed is a set of T1MMON Rev. 02A PROMs for the Series/100
main board.  This set consists of one Rev. 02A PROM from bit 0 to
bit 7 and one Rev. 02A PROM from bit 8 to bit F.

.h1;Compatibility

T1MMON Rev. 02A is compatible with earlier versions of software
running on the CS/100 and NCS/150.

.h1;Installation

Electro-static discharge (ESD) can damage PROMs and other circuit
board components.  Do not remove a circuit board or PROM from its
static protective package prior to installation.  When handling
any circuit board or PROM, avoid touching pins, leads, solder
connections, or gold-plated edges.  Failures resulting from ESD
may not be covered by your warranty.

To install the PROMs on the Series/100 main board, follow these
steps:

1.  Locate component positions U67 and U68 on the main board.
Refer to Figure 1 for information on component positions.

2.  Use a PROM-pulling tool to remove the T1MMON PROMs currently
occupying positions U67 and U68.  Take note of the orientation of
the notch in each old PROM, because the new PROMs must be
oriented in the same direction.

3.  If the rows of pins are too far apart to fit into the
sockets, press them closer together by pushing one row of pins
against a flat surface.

4.  Gently push the T1MMON PROM Rev. 02A marked 0-7 into the
socket at position U67.

5.  Gently push the T1MMON PROM Rev. 02A marked 8-F into the
socket at position U68.

6.  A shorting plug is located at configuration area E42 near the
ribbon connector for the floppy disk drive.  If your system is a
CS/100, which has a 48 TPI disk drive, be sure that the shorting
plug connects pins 2 and 3.  If your system is an NCS/150, which
has a 96 TPI disk drive, be sure that the shorting plug connects
pins 1 and 2.

.h1;New Features

T1MMON Rev. 02A supports double-sided 48 TPI disk drives on the
CS/100.  This feature was not implemented in T1MMON Rev. 01F or
earlier.

.h1;Bugs Fixed

T1MMON Rev. 02A reduces the chance of losing back-to-back
Ethernet packets during transmission.

.h1;Miscellaneous

To avoid being invoiced for the new PROM set, return the old set
to 3Com within 30 days.

If you have any questions, please contact an authorized 3Com
service representative for assistance.

