Black Box MDR100A-R5, User Manual

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Page 38
Chapter 5: Configuration
Table 5-2 (continued). S Register settings.
y < command command name > x Description
S110 Data Format This register determines the format of the data on the serial port.
The default is 8 data bits, No parity, and 1 Stop bit.
Values:
1 8N1 6 7N2
2 8N2 7 7E1
3 8E1 8 7O1
4 8O1 9 7E2
5 7N1 10 7O2
S112 Packet Max Size Determines that maximum number of bytes from the connected device that should
be encapsulated into a packet. Large packet sizes may produce the best data
throughput; however, a smaller packet is less likely to become corrupted and, if it
does, is retransmitted with a lesser impact on network traffic. The default setting of
255 bytes is suited to most applications.
Values (bytes):
1–256
255
NOTE: If you plan to adjust S112, consider data rate, wireless link rate, and the hop
interval (S102, S103, S109).
S113 Packet
Retransmissions This register determines the maximum amount of times that a packet will be retrans-
mitted (in addition to the initial transmission), noting the following specific behaviors
in various network topologies:
PMP: Master will retransmit each data packet the exact number of times specified in
its S113; Slave will retransmit only if necessary, and then only until a given packet is
acknowledged or the value of the Slave’s S113 is reached.
PTP: Modem will retransmit to its counterpart only if necessary.
Values:
0–255
5
NOTE: In a PMP system, set S113 to the minimum value required as, effectively, the
data throughput from Master to Remote is divided by 1 plus the number
stored in S113.
S115 Repeat Interval S115 determines the number of slots that are available within a window of
opportunity for Remote units to submit channel requests to the Master modem.
For a large number of remotes, the value of S115 should be set relatively high:
Remotes will randomly contend for the ability to access the channel request slots.
For a small number of Remotes, keep S115 closer to the default value so as to not
“waste bandwidth” by maintaining a relatively large window housing a greater-than-
necessary number of channel reservation request slots.
In a TDMA-type system, S115 may be set to 1, because the Remotes are not able to
request a transmission channel, the Master polls each Remote for data.
Values (Hop Intervals)
1–255:
3