User's Manual

32 MDS TransNET I/O Guide MDS 05-2708A01, Rev. A
When the SEND command is issued without parameters, the cumulative
retransmission count is shown. A value of 1 represents the default selection,
meaning “normal, non-robust operation.” Values greater than 1 successively
improve the chance of successful data delivery in spectrally harsh
environments. (Note that the SEND count for a remote radio is only viewable
when the remote is synchronized with its master station.)
There are two formats for entering the
SEND command. One format (SEND n)
can be used only at the master station, and selects the base transmission count
for the entire network. The other format (SEND +n or –n) can be used at any
radio in the network, and provides a means to customize the transmission count
locally at each radio, as a delta (amount of change) from the base.
For both formats,
n represents number between 1 and 10; for the “delta” format
a value of zero is also permitted. The net transmission count for a particular
radio is determined by adding the local “delta” (+n or –n) to the base
transmission count for the network. The net transmission count is
automatically bounded to the range 1..10, irrespective of the delta. The
combination of the two formats provides a means to highly customize the
retransmission behavior of network.
Higher retransmission counts come at the cost of increased latency and
reduced data throughput. With
BUFF ON, the radio maintains seamless
operation based on timing derived from the network SEND value. The use of
any tailored SEND values (e.g. SEND +/-x) within the system may disrupt
seamless operation. This is because the increased latency makes seamless
mode impractical. Table 2 lists the maximum cumulative SEND count for
continuous operation, at some typical data rates.
SETUP
This command sets up the transceiver for checking antenna SWR or
transmitter power with external measuring equipment. Do not use this mode
during normal operation.
When the
SETUP command is entered, the prompt changes to SETUP>, and:
• Hopping is disabled.
• Synthesizer frequencies are reset to the test frequencies specified by
the
TX and RX commands.
• The radio can be keyed using the
KEY command. DKEY is used to
unkey the radio. (If the radio is left in a keyed state it is automatically
unkeyed after several minutes.)
• The
RSSI is sampled in a raw, continuous fashion regardless of
whether the unit is a master or a remote.
Entering
Q or QUIT returns the system to normal operation.
Table 7. Baud Rate vs. Maximum SEND Count
BAUD
RATE
(BPS)
XSHORT
(max. send
count)
16 ms
(max. send
count)
20 ms
(max. send
count)
25 ms
(max. send
count)
32 ms
(max. send
count)
SHORT
(max. send
count)
NORMAL
(max. send
count)
LONG
(max. send
count)
1200 3 8 10 10 10 10 10 10
2400 N/A 4 5 5 5 7 8 8
4800 N/A 2 2 2 2 3 4 4
9600 N/A N/A N/A N/A N/A N/A 2 2