Ref: 99980131
Title: M0ASYN PROM Revision 18C
Date: 7/2/87

Copyright 3Com Corporation, 1991.  All rights reserved.

Enclosed is a set of M0ASYN Revision 18C PROMs for the SIO-A
board.  This set consists of one Revision 18C PROM from bit 0 to
bit 7 and one Revision 18C PROM from bit 8 to bit F.

.h1;Installation

To install the Revision 18C PROMs on the SIO-A board, follow
these steps:

1.  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.

2.  On the SIO-A board, gently push the PROM marked 0-7 into the
socket marked 0-7.  Then gently push the PROM marked 8-F into the
socket marked 8-F.  Be sure that the notch in each PROM is
oriented in the same direction as the corresponding notch in the
currently installed set of PROMs.

.h1;New Features

The following features, which were not present in M0ASYN Revision
17F or earlier, have been implemented in M0ASYN Revision 18C:

1.  It now supports eight-bit data transfer plus parity
checking.  The parity can be odd, even, or none.

2.  The ECM character can be sent both in band and out of band.

3.  After you have set the BAud parameter to LowAutoBaud, your
terminal's baud rate can be set to 300, 600, 1200, or 2400.
If the BAud parameter is set to HiAutoBaud, your terminal's
baud rate can be set to 2400, 4800, 9600, or 19200.

.h1;Bugs Fixed

The following problems, which were present in M0ASYN Revision 17F
or earlier, have been corrected in M0ASYN Revision 18C:

1.  The CS/1 now works properly when a long break is received.

2.  The ^Q character, which is the XON character, can be
embedded in terminal responses.  In the past, the first XON
character in a character stream was recognized as a flow
control character, and any subsequent XON character would
be passed to the host as data.  Now the extra XON
characters are stripped before the character stream is sent
to the host.

3.  A long break is no longer lost when DTR drops.

4.  When the UseDCDout parameter is set to ToggleonDisc, the
DCD output signal will be deasserted after disconnection
for at least approximately 250 milliseconds instead of 100
milliseconds.

5.  The ENQ/ACK flow control options, which were never
supported by the M0ASYN firmware, have been eliminated.

.h1;Miscellaneous

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

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

