User's Manual

UL865-N3G Hardware User Guide
1VV0301177 Rev 2– 2015-04-20
Reproduction forbidden without written authorization from Telit Communications S.p.A. - All Rights
Reserved. Page 44 of 70
Mod. 0805 2011-07 Rev.2
The signals of the UL865-N3G V2 serial port are:
RS232 Pin
Number
Signal
UL865-N3G V2
Pad Number
Name Usage
1 DCD - dcd_uart 1 Data Carrier Detect
Output from the UL865-N3G V2 that
indicates the carrier presence
2 RXD - tx_uart 8 Transmit line *see Note
Output transmit line of UL865-N3G V2
UART
3 TXD - rx_uart 7 Receive line *see Note
Input receive of the UL865-N3G V2
UART
4 DTR - dtr_uart 4 Data Terminal Ready
Input to the UL865-N3G V2 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 UL865-N3G V2 that
indicates the module is ready
7 RTS -rts_uart 5 Request to Send
Input to the UL865-N3G V2 that controls
the Hardware flow control
8 CTS - cts_uart 6 Clear to Send
Output from the UL865-N3G V2 that
controls the Hardware flow control
9 RI - ri_uart 2 Ring Indicator
Output from the UL865-N3G V2 that
indicates the incoming call condition
The following table shows the typical input value of internal pull-up resistors for RTS DTR
and TXD input lines and in all module states:
STATE
RTS DTR TXD
Pull up tied to
ON
5K to 12K 1V8
OFF
Schottky diode
RESET
Schottky diode
POWER
SAVING
5K to 12K 1V8
The input line ON_OFF and RESET state can be treated as in picture below