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Feature Reference DART 300 Modem
Page 56 2110212 Rev 1.0
Specifying a list of Service Provider Network Identifier (SPNI) numbers is optional and relates
more to roaming. This is not usually an issue in DART 300 installations. Since roaming rates can
be expensive, it may be to your benefit to obtain more than one CDPD account. For example, if
you commonly travel between two areas served by two different carriers, you may want to have an
account for each of the areas. Then as you travel from one area to another, you can switch
accounts, rather than incur the expense of roaming. However, most CDPD carriers currently have
Interoperations (Interop) Agreements and there is no roaming charge.
If the table is empty, the SPNI matching feature is disabled.
NOTE
If you set SPNI matching and also use +WPCHAN to assign a channel manually, the
modem will not acquire the assigned channel if the SPNI fails to match. The modem
will not be able to register because it will not look for another channel if you have
manually set a channel. The status of channel acquisition can be checked using
+WPRSSI.
SPNI Table Configuration
To manage the use of SPNI matching using AT Commands enter the following commands (the
AT is omitted for brevity):
Read the Current SPNI Table
1. +WPSPNI? Displays the SPNI Table. If the table is empty then SPNI matching is disabled.
If there is at least one entry then SPNI matching is enabled.
Disable SPNI Matching
1. +WPSPNI= By not entering parameters, the table will be erased. An empty table disables
SPNI matching. Note that the entry must be void; a zero is a legitimate SPNI.
Enable SPNI Matching
1. +WPSPNI=n[,n[,…n]] where n is a SPNI value and multiple values are separated by
commas. The list of parameters provided will replace any previous table. You cannot append
entries to an existing table. To add a SPNI to an existing list, the entire table must be re-
entered including the new addition. You may enter up to ten values in the table. By entering
one or more SPNI values, the SPNI matching feature is automatically enabled.
7.2.1.4. Determining Channel Acquisition Status
At any time AT command access is available, the following methods can be used to determine the
status of channel acquisition.
+WPRSSI (RSSI and Channel State)
This command reports four data items: signal strength, channel state, registration state,
and channel number. The second item in the list will report 1 if the modem is scanning
(or has not acquired the channel), and 3 when the modem has acquired a channel. This is
the most reliable indicator of channel acquisition for use.
While scanning, the channel number will be the one the modem is currently attempting to
acquire. Once acquired, the channel number will show the channel the modem has
locked on to.
If +WPCHAN=n was used to force a channel number which it cannot use, this command
will report a status of scanning even though the modem is not in fact trying other
channels.
+WS200? (Current Channel Number)
This register reports 0 when the modem is scanning; otherwise the current channel the
modem has tuned to is displayed. The modem may not have acquired the channel for
use.