DART 200 CDPD Modem User’s Guide 2 Installation and Setup
PN1197-00 Revision 1.0 2-13
• By viewing the Network Status Register (S-Register 57) with the
AT&V command or the ATS57? command. This is the
recommended method, because viewing S-Register 57 shows other
useful information, as shown in Figure 2-3
Figure 2-3. Viewing the network S-Register (S57)
ATS57?
160
OK
A value of 128 (bit 7 on) or higher indicates that the modem acquired
a channel. If auto-registration at power on (AT\R4) is specified, then
the value is 160 (bits 5 and 7 on) or 161 (bit 0 also on) indicating that
it completed registration.
If the DART cannot acquire a channel, move the antenna to a better
location. To determine the best location for the antenna you need some
indication of received signal strength. This is given by the RSSI; one of
the radio resource values. View RSSI with the ATS102? or the AT&V+
command.
Figure 2-4 is a snapshot of the CDPD channel at a specific point in time.
View this data several times to see if the modem is staying on a single
channel (S-Register 100) or continues to search. If the value in
S-Register 101 is a zero, then the search is continuing.
Figure 2-4. Monitoring the CDPD channel
at&v+
DART 200
S100:00799 S101:00001 S102:-0073 S103:00002 S104:00040 S105:00000
S106:00001 S107:00000 S108:00022 S109:00010 S110:00079 S111:00001
S112:00000 S113:00000 S114:00000 S115:00000 S116:00000 S117:00000
S118:00018 S119:0FFFF S120:00000 S121:00002 S122:00000 S123:00002
S124:00030 S125:14400 S126:00005
If the modem cannot acquire a usable channel (S-Register 101 = 1) after
a few minutes there are several possible causes:
• The signal strength is too weak
• The cell is not currently CDPD capable (check with your cellular
carrier)
• The modem has an incorrect channel restriction configuration. Use
the AT&V command to check the \Jn setting
• The side setting is wrong. Use the AT&V command to check the
\Nn setting
• There is an interference problem
• The modem is faulty