
GL865-DUAL V3 Hardware User Guide
1vv0301018 Rev.5 – 2013-08-05
Reproduction forbidden without written authorization from Telit Communications S.p.A. - All Rights Reserved.
Page 40 of 76
Mod. 0805 2011-07 Rev.2
The signals of the GL865-DUAL V3 serial port are:
RS232 Pin
Number
Signal
GL865-DUAL V3
Pad Number
Name
Usage
1
DCD - dcd_uart
1
Data Carrier Detect
Output from the GL865-DUAL V3 that
indicates the carrier presence
2
RXD - tx_uart
8
Transmit line *see Note Output transmit line of GL865-DUAL
V3 UART
3
TXD - rx_uart
7
Receive line *see Note Input receive of the GL865-DUAL V3
UART
4
DTR - dtr_uart
4
Data Terminal Ready
Input to the GL865-DUAL V3 that
controls the DTE READY condition
5
GND
32, 33, 35, 36, 46
Ground
Ground
6
DSR - dsr_uart
3
Data Set Ready
Output from the GL865-DUAL V3 that
indicates the module is ready
7
RTS -rts_uart
5
Request to Send
Input to the GL865-DUAL V3 that
controls the Hardware flow control
8
CTS - cts_uart
6
Clear to Send
Output from the GL865-DUAL V3 that
controls the Hardware flow control
9
RI - ri_uart
2
Ring Indicator
Output from the GL865-DUAL V3 that
indicates the incoming call condition
NOTE:
According to V.24, RX/TX signal names are referred to the application side, therefore on the
GL865-DUAL V3 side these signal are on the opposite direction: TXD on the application side
will be connected to the receive line (here named TXD/ rx_uart ) of the GL865-DUAL V3
serial port and vice versa for RX.
NOTE:
For a minimum implementation, only the TXD and RXD lines can be connected, the other
lines can be left open provided a software flow control is implemented.
NOTE:
In order to avoid a back powering effect it is recommended to avoid having any HIGH logic
level signal applied to the digital pins of the GL865-DUAL V3 when the module is powered
off or during an ON/OFF transition.