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3.0 Configuration
3.3.3 Unit Addressing
In a Point to Multipoint Network each unit must have a unique unit address, which can be
configured using register S105. Duplicate addresses may result in unpredictable problems in
the network. In a PMP Network data flow is such that data from the Master is sent to all units
by setting the destination address (S140) to 65535, meaning data is broadcast to all units.
3.3.4 Retransmissions
Packet Retransmissions can be used to ensure data reaches its intended destination by re-
sending the same packet over and over. In Point to Multipoint system data is not acknowl-
edged by the destination, meaning data will be transmitted, an additional number of times
specified by S113, resulting in a significant impact on system performance. The more times a
modem retransmits data, the more the overall throughput of the system is reduced. To adjust
the retransmission rate, use register S113, the default value is 5 (+ the initial transmission).
Although, this number should be as low as possible to keep as much bandwidth in the system
as possible.
S113 = 5 -
Packet Retransmissions (0-254)
Retransmissions are typically used in noisy environments to combat interference and low sig-
nal strength, ensuring data is received at the intended destination.
3.3.5 Network Synchronization
Network Synchronization is what allows all units to hop from frequency to frequency at the
same time.
For units to synchronize with the network, each unit must have the same:
- Network ID (S104)
- Network Type (S133)
Sync Timeout
Once synchronized to the network the unit does not need to receive sync data often to keep
track of where the system is supposed to be (in time and frequency). The sync Timeout de-
fines the number of hops where no sync data is received from a Master and/or Repeater be-
fore losing sync. In other words, how long a unit will remain synchronized with the network
without receiving any sync packets before it gives up and loses sync.
S248 = 100
Sync Timeout (4-65534)
Setting a value too low will cause the unit to lose sync easily and time will be wasted trying to
re-sync to the network. Several hops can go by without receiving a sync packet, and this is
completely normal. If this value is set too high, the unit will assume for a long time that the
network is still out there, when especially in mobile applications, it may not be.
