Network Status Indication - SimCom SIM900B Hardware Design

HIGH
LOW
However, if the module is used as caller, the RI will remain high. Please refer to the following figure.

3.12 Network Status Indication

The NETLIGHT pin can be used to drive a network status indication LED. The status of this pin is listed in
following table:
Table 12: Status of the NETLIGHT pin
Status
Off
64ms On/ 800ms Off
64ms On/ 3000ms Off
64ms On/ 300ms Off
A reference circuit is recommended in the following figure:
SIM900B_Hardware Design_V2.01
RI
Idle
Figure 27: RI behaviour of data calling as a receiver
Figure 28: RI behaviour of URC or receive SMS
Figure 29: RI behaviour as a caller
SIM900B behavior
SIM900B is not running
SIM900B not registered the network
SIM900B registered to the network
GPRS communication is established
Establish the call
Hang up the call
Ring
31
Smart Machine Smart Decision
2012-05-07