User's Guide

The Operational View SB300 Series
Page 36 Proprietary and Confidential 2110059 Rev 1.0
5.4. Monitoring the Network Connection
Prior to finding a channel, many query items will return 0. Once locked onto a CDPD channel, the
modem can provide several pieces of information about the connection. Additional information is
available regarding the registration of the modem.
5.4.1. Radio Signal Monitors
5.4.1.1. Signal Strength
There are two primary monitors of signal strength.
A “percentage” value can be read from register +WS50 (Normalized Signal Strength). It reports a
value from 0 to 100 where 0 is imperceptible and 100 is full signal.
The Receive Signal Strength Indication (RSSI) is more informative. It is read with the RSSI and
Channel State command (+WPRSSI). It reports:
• Signal strength in dBm (-113 to -30),
• State of the channel (1 - Scanning, 3 - Acquired, 4 - Sleeping),
• Registration Status (0 no, 1 yes)
• Channel number (0 if scanning)
Note that the registration status reported here is that of the Active NEI Index (+WS197) which
may point to a NEI other than one that is in fact registered. Consult register +WS56 to check the
registration status of the modem.
5.4.1.2. Current Channel
The channel number is available from register +WS200. A value of 0 indicates the modem has
not acquired a channel.
5.4.1.3. SPNI of the Connected Carrier
When the modem has locked onto a channel (whether registered or not) the Service Provider
Network Identifier (SPNI) for that channel can be read with the command +WCID.
5.4.1.4. Cell Number
Although not important in most circumstances, the number of the current CDPD base station is
available from register +WS210.
5.4.2. Registration Status
The status of the modem’s registration can be read at register +WS56 (Network Registration
Status). A value of 1 indicates the modem is registered. A value of 0 indicates that it is not
registered.
5.4.2.1. Registration Mode
The current setting of auto-registration is found in register +WS173. A value of 1 indicates
automatic registration is enabled, 0 indicates manual registration mode.