Date   : Wed, 21 Mar 1984 23:36:00 MST (Wed)
From   : Keith Petersen <W8SDZ@Simtel20.ARPA>
Subject: New TRS-80 Model-I overlay for MDM7xx.

Dave Towson has uploaded a new TRS-80 Model-I overlay for MDM7xx.
It's now available on SIMTEL20 as MICRO:<CPM.MODEM7>M7R1-3.ASM.
Here's what's new in it:

From: David Towson (CSD) <towson at amsaa>
To:   Keith Petersen <w8sdz>
Re:   New TRS-80 Model-I overlay for MDM7xx.

Compared with the existing R1 overlay, the new one has the following
differences:

a.  The installation instructions are correct for the current size of
    MDM7xx.COM.

b.  The code is fully commented.

c.  Material from the general-purpose overlay file, but meaningless in
    a TRS-80 Model-I/III context has been removed.

d.  Labels having meaning in the MDM7xx.ASM context have been equated
    to labels having more meaning in the TRS-80 context, making the
    program more readable (in my opinion).

e.  The label ACKNAK has been changed to NORETRY to reflect current 
    usage, and an explanation is given in the comments.

f.  Equates for NUMLIB address, XFRSIZ and SHOWHEX have been added
    to allow use of new capabilities in MDM728.  They work.

g.  The GOODBYE routine turns off DTR and RTS, and leaves them off.
    They can be turned back on by sending a BREAK in terminal mode 
    (300 millisecond BREAK is supported).


I have experimented with a 4K protocol-transfer buffer, and I really like
it.  Sixteen-K works okay for me, but takes a VERY long time to load in the
protocol-send mode.  With 4K, the pause is quite short (less than 2 seconds),
and very unlikely to cause a timeout on the receive end.