User's Manual

GWM300 Hardware Interface Overview
3.4 Molex Microfit Connector
26
 GWM300_HIO_v01 2016-01-26
Confidential / Released
Page 23 of 35
3.4.1 RS-232 Interface
The RS-232 interface is implemented as a serial asynchronous transmitter and receiver con-
forming to ITU-T V.24 Interchange Circuits DCE. Based on the conventions for DCE-DTE con-
nections it communicates with the host application (DTE) using the following signals:
• Port TxD @ application sends data to TXD0 of the GWM300
• Port RxD @ application receives data from RXD0 of the GWM300
The serial interface (also called ASC0) is configured for 8 data bits, no parity and 1 stop bit, and
is by default operated at a fixed baud rate of 9600bps, but can be configured for bit rates from
1200bps to 921kbps. Autobauding supports bit rates from 1.2kbps to 230kbps. Hardware hand-
shake using the RTS0 and CTS0 signals and XON/XOFF software flow control are supported.
In addition, the modem control signals DTR0 and DCD0 are available. There are different
modes of operation that can be set with AT commands.
3.4.2 Power Supply
The power supply of the GWM300 has to be a single voltage source of V
PLUS
=5V…26V capable
of providing a peak current of about 2.5A at 15V during an active transmission. The uplink burst
causes strong ripple (drop) on the power lines. The absolute minimum voltage during drops
must be >5V.