MDS 05-4846A01, Rev. F
SD Series Technical Manual
91
The disadvantage to passive operation is that it takes longer to convey
the reprogramming information since it is must be attached to existing
data transactions. See Table 18 for the approximate times needed for
passive reprogramming.
NOTE:
It is possible for Remote radios receiving a firmware upgrade
to complete reprogramming before the initiating station does.
This is because transmissions are sent out “broadcast style”
and will be sent up to the number of times entered in the
Retry
Count
parameter of the radio. In a strong signal environment,
the image may be received successfully the first time, but the
initiator does not know this, and continues broadcasting image
data blocks until the specified retry count has been reached.
OTA Reprogramming Overview
The “Root” is the central location from which polling originates. Other
locations in the network should be designated as “Nodes” which are the
receiving stations. Over-the-air firmware upgrades should always be
initiated from the Root. This ensures that all radios in the network will
be properly updated.
Once an OTA reprogram session has started, the initiating radio selects
either the active or inactive image stored in its non-volatile storage
which is copied to all the other radios in the network.
The initiator broadcasts a series of messages to one or more remote
Nodes to accomplish the reprogramming process. The “broadcast”
method is used to program the greatest number of radios in the shortest
amount of time, however, the initiating station remains unaware of the
number or success of downstream radios participating in reprogram-
ming.
During reprogramming the status of the reprogramming will be avail-
able on all the radios participating in process. Because the initiator is
“broadcast-only” this status can only indicate progress toward sending
out of
all
messages. On the Nodes, the progress toward completion of
reception of reprogramming information is indicated.
Table 18. Approximate Reprogramming Times—
Passive Mode
Modem Speed
(bps)
Approximate Time Required
4800
6 hours, 7 minutes
9600
1 hour, 30 minutes
19200
1 hour, 30 minutes
Radio assumptions: Signal strength -85 dBm or
stronger, Packet Size: 40, Block Size: 512, Retry: 3
Polling assumptions: Serial polling with 1-second poll
time, sending random data at 50-100 bytes. Slower
polling times will significantly increase completion time.
