Telit Wireless Solutions HE910, Hardware User'S Manual

Page: 78 / 111

HE910 Hardware User Guide
1VV0300925 Rev. 32 Page 78 of 111 2019-11-25
MODEM SERIAL PORT 1 (USIF0)
The serial port 1 on the HE910 is a +1.8V UART with all the 7 RS232 signals.
It differs from the PC-RS232 in the signal polarity (RS232 is reversed) and levels.
RS232
Pin #
Signal HE910
Pad Number
Name Usage
1 C109/DCD N14 Data Carrier Detect Output from the
HE910 that indicates
the carrier presence
2 C104/RXD M15 Transmit line *see
Note Output transmit line
of HE910 UART
3 C103/TXD N15 Receive line *see
Note Input receive of the
HE910 UART
4 C108/DTR M14 Data Terminal
Ready Input to the HE910
that controls the DTE
READY condition
5 GND M12, B13,
P13, E14 … Ground Ground
6 C107/DSR P14 Data Set Ready Output from the
HE910 that indicates
the module is ready
7 C106/CTS P15 Clear to Send Output from the
HE910 that controls
the Hardware flow
control
8 C105/RTS L14 Request to Send Input to the HE910
that controls the
Hardware flow
control
9 C125/RING R14 Ring Indicator Output from the
HE910 that indicates
the incoming call
condition