hardware design v1 00 2

Table Of Contents
Smart Machine Smart Decision
Figure 32: RI behaviour of URC or receive SMS
However, if the module is used as caller, the RI will remain high. Please refer to the following figure.
Figure 33: RI behaviour as a caller
4.12 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 13: Status of the NETLIGHT pin
Status SIM900R behavior
Off SIM900R is not running
64ms On/ 800ms Off SIM900R not registered the network
64ms On/ 3000ms Off SIM900R registered to the network
64ms On/ 300ms Off GPRS communication is established
A reference circuit is recommended in the following figure:
Figure 34: Reference circuit of NETLIGHT
SIM900R_Hardware Design_V1.00 33 2012-07-20