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Figure 13: Dimensions of 10-line cable
P1
Terminal signal
Signal name
I/O
Comments
3
GPIO4
I/O
Configurable by AT commands
4
GPIO3
I/O
5
GPIO2
I/O
6
RING
O
RING Indicator
7
RTS
I
Request to send
8
CTS
O
Clear to send
9
TXD
O
Transmit Data (RS485 TXD)
10
RXD
I
Recieve Data (RS485 TXD)
11
DCD
O
Data Carrier Detected
12
DTR
I
Data Terminal Ready
6.3.1
GPIO interfaces
HDM1004G provides 4 GPIO pins. The output voltage level of the GPIO can be set by the
AT command “AT+ SGPIO”. The input voltage level of the GPIO can also be read by the AT
command “AT+ SGPIO”. The following table shows the detail commands about GPIO.
Table 5: AT+SGPIO Control the GPIO
AT+ SGPIO Control the GPIO
Test Command
AT+SGPIO=?
Response
+SGPIO: (0-1),(1-12),(0-2),(0-1)
OK
Parameters
See Write Command
Write Command
Response