EG_GenPro78e_1003_UG_007_UK
Page 29 / 41
Description and non-contractual illustrations in this document are given as an indication only.
ERCO & GENER reserves the right to make any modifications.
7.3 RS232 serial link
7.3.1 General
The RS232 interface provides a level translation (V24/CMOS
⇔
V24/V28) between the GSM module DCE)
and the PC COM port (DTE).
The RS232 interface is protected internally (ESD protection) against external electrostatic spikes.
Filter guarantees:
Input/output EMI/RFI protection,
Signal
smoothing.
The following signals are available:
TX data (CT103/TX)
RX data (CT104/RX)
Request To Send (CT105/RTS)
Clear To Send (CT106/CTS)
Data Terminal Ready (CT108-2/DTR)
Data Set Ready (CT107/DSR)
Data Carrier Detect (CT109/DCD) : optional Buzzer output,
Ring Indicator (CT125/RI) / 3.8V : optional 3.8V supply for GenBlue xxe.
RS232 signals
The DSR signal is always present in a high level when the modem is power supplied.
The RS232 interface allows a certain amount of flexibility in the use of its signals. For example, after
configuration (see command
AT+IFC
) the modem may operate in the 3-wire mode using only the TX, RX
and GND signals. However, the TX, RX, GND, CTS and RTS signals will also be required for GPRS
applications and Xmodem upgrade. This is not the case for the DTR, DSR, DCD and RI signals which may
be not used.
