9602-N User Guide Version A
Document Number: 451-92695-001A
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currently visible, then the update period can be as long as two minutes, depending on how long
the lack of satellite visibility existed. This is because the 9602-NAL attempts to conserve power
by increasing the ring-search interval while the satellites are not visible. Every time a ring search
fails, the time to wait is increased until it reaches a limit at 120 seconds. The wait time between
search windows is reset to 4 seconds every time a search succeeds.
If Network Available is currently off, you may still attempt an SBDI[X] session. This will force the
9602-NAL to look for the Ring Channel immediately, and on finding it, to attempt to send the
message. In this case, Network Available will not come on immediately. Network Available does
not turn on while in a +SBDI session. It will, however, turn on 4 seconds later, assuming that the
Ring Channel is present. After the SBD session completes, the 9602-NAL performs a new Ring
Channel search sequence, at the end of which Network Available gets turned on. That can take
between 4 and 12 seconds. If the +SBDI attempt fails to find the ring channel, the search
window does not reset to 4 seconds. Note that the behavior of +CIEV:1 is identical to that of the
Network Available output.
3.7
S-M
ETER
P
ERFORMANCE
The S-meter readings reported over the AT command interface indicate the signal strength of a
9602-NAL. Be careful when using the S-meter readings for comparisons between devices. Of
particular note are the following:
1.
There is a 0.5 dB tolerance on calibrating the S-meter.
2.
Each signal strength bar represents a 2 dB increment.
3.
Multiple ring channels can be present at the same time, so units can lock to different
signals.
4.
If the reading is near the decision threshold, it would be easy to see a 1-bar difference.