Epson Multi-mode Data Controller MFJ-1278B - Manual (Page 354)

MFJ-1278B MULTI-MODE APPENDIX F 2400 BPS PACKET
MFJ-1278B 2400 BPS PACKET
If your MFJ-1278B does not have the 2400 bps packet capability, then the user can easily
install the proper hardware. The user can purchase the optional MFJ-2400 BPS modem, and
is easily installed. Installation is simple, because your MFJ-1278B is equipped with all the
appropriate connectors necessary to make this installation quick and easy without
modifications or soldering. If you have the MFJ-1278BT the 2400 modem is already
installed inside the unit.
With the MFJ-2400 modem installed, your MFJ-1278B is capable of operating 300, 1200 or
2400 baud packet. With the MFJ-2400 BPS modem has no effect on the 300 and 1200 baud
packet mode operations. The addition of the 2400 modem feature will in no way require any
internal modification to your transceiver.
2400 BPS PACKET SETUP
All the default parameter settings for 1200 baud packet operation can be used for 2400 bps
packet operation. 2400 bps operations need no special setup or parameter changes. There
are however, some changes that the user can make later on to the MFJ-1278B parameters that
will enable you to improve the speed of the throughput performance of the 2400 bps
operation. The "honing" of the parameters may not seem like much, but we have found that
at 2400 bps, the MFJ-1278B seems to be more responsive to the TXDELAY, DWAIT,
RESPONSE and SLOTTIMES. When using direct connects and good paths, the user can
increase the MAXFRAME and PACLEN commands to allow larger packets to be moved
during each transmission. When returning to the active throughput frequencies, these two
commands should be reduced to their original settings. You may find that if you were using a
TXDELAY of 50, then a TXDELAY of 40 will now perform better. The DWAIT
command can be shortened or lengthened to suit the AGC recovery time of your radio. For
instance, if you have been running the DWAIT of 16, it may now perform better at DWAIT
of 12 or even 10. The FRACK will appear to exercise more at 2400 also.
2400 BPS operation really shows its place in the packet world when used to pass large
ASCII, BINARY and PICTURE files. It is always good to use clear frequency and/or use
direct connects to the target station rather than going thru a node or digipeater. The reason is
obvious. There are few 2400 nodes at the present time. However, it should be pointed out
that implementation of a 2400 node is just as easy as building and using a 1200 node.
To select 2400 packet operation, under the CMD: command prompt, type:
MODE VP,2400 <CR>
The MFJ-1278B changes its operating mode to 2400 bps packet. The TURBO LED will