Rhydo GSM-1936, Руководство пользователя

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www.rhydolabz.com SIM900 GSM/GPRS TTL UART Modem - User Manual
W e b r i n g t h e w o r l d t o y o u … … . . Page 5
PIN DESCRIPTIONS
PIN PIN NAME DIR DETAILS
VIN Power Supply PWR Power Supply Input (4.2-13V DC,1A)
GND Ground PWR Ground Level of Power Supply
V_
Interface
Interfacing
Voltage
PWR
Interfacing Voltage Input for on board voltage level conversion (3V3 or 5V).
If the modem has to be interfaced with a 5V microcontroller, the input to this pin
should be 5V DC and if the modem has to be interfaced with a 3V3 microcontroller,
the input to this pin should be 3.3V DC.
TXD Transmit OUT
Outputs data bytes at voltage Level same as the V_Interface Pin
– Usually connected to the Rx pin of the microcontroller
RXD Receive IN
Receives data bytes at voltage Level same as the V_Interface Pin
– Usually connected to the TX pin of the microcontroller
GND Ground PWR Ground Level of Interfacing Signals
/RESET Reset Input IN
Active low Reset pin to reset the modem , Pull down this pin to reset the modem using a
open collector output or switch- Normally leave open
-No on board level Conversion
RTS
Request to
send
IN
Used For hardware flow control. If needed ,can be shorted with CTS using J1 at bottom
side, in default left open—With on board level Conversion
CTS Clear to send OUT
Used For hardware flow control. If needed , can be shorted with RTS using J1 at
bottom side, in default left open-—With on board level Conversion
PWRKEY Power Key IN
Pin for MODEM On/Off externally using open collector transistor or Switch.
-No on board level Conversion
NETLIGHT Net Led OUT
Open Collector output for connecting the Connection status LED externally
-Use 1k ohm resistor in series with LED
STS Status LED OUT
Open Collector output for connecting the Status LED externally
-Use 1k ohm resistor in series with LED
RI Ring indicator OUT
Pin to interrupt the Host / Microcontroller to indicate Call, SMS, Error ect.
-No on board level Conversion
DTR
Data Terminal
Ready
IN
Input pin used to switch the modem to and from the command mode
- Normally leave open -— With on board level Conversion