16
MHX-900 Operating Manual: Chapter 3 Configuration Options
In a point-to-point network,
the master and slave must be
set to the same hopping
interval.
In a point-to-multipoint
network, the hopping
interval is controlled by the
master. The slave units will
use the hopping interval
setting from the master.
S Register 109 - Hopping Interval
This option determines the frequency at which the modems change channel.
Note that all modems must have the same hopping interval setting.
The allowable settings are:
1
25 msec
2
50 msec
3
100 msec
4
150 msec
*5
200 msec
6
250 msec
7
300 msec
8
350 msec
In Slave - Point-to-Multipoint operation, this parameter is determined by the
Master, and cannot be altered.
Packet Parameters
Packet Parameters define the characteristics of the internal packets or frames
which are transmitted. The settings should be set only by an expert since
adequate care must be taken to maintain reliability and optimum
performance. Packet Parameters will vary depending on the modem’s
Operating Mode.
S Registers 111 to 113 - Packet Parameters -Point to Point
Mode
In Point-to-Point (both Master and Slave), the following settings are
available:
S Register 111 - Minimum Size
This setting has a range of 0 to 255, and defines the number of bytes to
accumulate from the DTE before transmitting a packet. Setting this value to
0 ensures that all characters sent by the DTE are immediately transmitted.
The value may not exceed the maximum packet size.
S Register 112 - Maximum Size
This setting has a range of 1 to 255, and defines the maximum number of
bytes from the DTE which should be encapsulated in a packet. This value
should be greater than the minimum packet size, but not smaller than is
necessary for reliable communications. If the wireless link is consistently
good and solid, a maximum size of 255 will yield the best throughput
(depending on the higher level protocols of the connected equipment).
However, if the link is poor (
e.g.
, experiencing excessive interference) and
data is frequently retransmitted, the maximum packet size should be
reduced. This decreases the probability of errors within packets, and
reduces the amount of traffic in the event that retransmissions are required.
Since a smaller packet size results in a proportionally higher overhead and
lower overall throughput on a good connection, this should only be reduced
if many errors are being detected by CRC (see Radio Statistics option of
configuration).
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Страница 26: ...22 MHX 900 Operating Manual Appendix B Serial Interface...
Страница 28: ...24 MHX 900 Operating Manual Appendix C Sample Schematic Diagram...
Страница 30: ...26 MHX 900 Operating Manual Appendix D Modem Setup Overview...
Страница 32: ...28 MHX 900 Operating Manual Appendix E Technical Specifications...