Yaesu FT-7100M Operating Manual page 13

Note that 9600 bps packet transmit-deviation adjustment is very critical to successful opera-
tion, and can only be accomplished using a calibrated deviation meter (such as that found on
an FM Service Monitor used in a communications service center). In most cases, the Packet
Data Input level (set via a potentiometer inside the TNC) must be adjusted to provide a
deviation of ±2.75 kHz (±0.25 kHz). Check with your packet node's sysop if you have any
questions about the appropriate deviation level for your network. Note also that high through-
put on 9600 bps frequently requires strong signals, so you may wish to consider the use of
a directional antenna such as a Yagi for communication with high-speed packet nodes.
The setting of the 1200 bps Packet Data Input level is much less critical than it is at 9600 bps,
and satisfactory adjustment to the optimum (±2.5 ~ ±3.5 kHz) deviation can usually be done
"by ear" by adjusting the TNC's 1200 bps TX Audio Level potentiometer so that the outgo-
ing packets (as monitored on a separate VHF or UHF receiver) are approximately the same
level as (A) the DTMF tones or (B) the 1750 Hz Burst tone produced using the microphone.
Typical connections to a TNC are shown below.
Finally, note that the ("PCKT") M
or 9600 bps) independently for each band. If you have trouble getting your FT-7100M to
respond correctly during packet operation, check to be certain that you do not have Menu
#19 (PCKT) set to the wrong data rate.
FT-7100M Operating Manual
B S
ASE TATION
selection allows you to set the Packet data rate (1200
ENU
9600 bps Packet Setup
1200 bps Packet Setup
I
NSTALLATION
I
NSTALLATION
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