SIM900D Hardware Design
Figure31: RI behaviour of URC or receive SMS
Figure32: RI behaviour as a caller
3.15 Network Status Indication
The NETLIGHT can be used to drive a network status indication LED lamp. The working state of this pin is listed
in following table:
Table22: Working state of the NETLIGHT
State
SIM900D function
Off
SIM900D is not running
64ms On/ 800ms Off
SIM900D does not find the network
64ms On/ 3000ms Off
SIM900D find the network
64ms On/ 300ms Off
GPRS communication
Provide a reference circuit for user, shown as following figure:
SIM900D_Hardware Design_V1.04
2010.10.09
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