MTX-IND-V2 Industrial Featured GSM-GPRS terminal modem http://www.matrix.es
MTX-IND-V2 User Manual V.1.1
Page. 22
Subject to change without prior notice
RS232 Interface
MTX-IND-V2 Terminal is designed for use as a DCE (data circuit-terminating equipment). Based on the
conventions for DCE-DTE connections, it communicates with the customer application (DTE- data
terminating equipment) using the following signals:
• Port TxD @ application sends data to TXD of MTX-IND-V2 Terminal
• Port RxD @ application receives data from RXD of MTX-IND-V2 Terminal
The RS-232 interface is implemented as a serial asynchronous transmitter and receiver conforming to ITU-
T V.24 Interchange Circuits DCE.
The electrical characteristics of the RS232 serial port signals are shown below:
Note: Outputs at 3kOhm load
• Includes the data lines TXD0 and RXD0, the status lines RTS0 and CTS0 and also the modem control line
RING0.
• ASC0 is primarily designed for controlling voice calls, transferring CSD, fax/GPRS data and for controlling
the GSM engine with AT commands.
• Full Multiplex capability allows the interface to be partitioned into three virtual channels, but with CSD
and fax services only available on the first logical channel. Please note that when the ASC0 interface runs
in Multiplex mode, ASC1 cannot be used.
• The RING0 signal serves to indicate incoming calls and other types of URCs (Unsolicited Result Code). It
can also be used to send pulses to the host application, for example to wake up the application from a
power saving state. To configure the RING0 line, use the following AT Command: AT^SCFG.
• By default it is configured for 11500 bps, 8 data bits, no parity and 1 stop bit.
• ASC0 can be operated at fixed bit rates from 300 bps to 460800 bps.
• Autobauding is not compatible with multiplex mode.
• Supports RTS0/CTS0 hardware flow control and XON/XOFF software flow control.
Pin Signal Dir Voltage
levels
Description Comments
49 RX
O
Min ±5V
Received data
48 TX
I
VILmax = 0.6V
VIHmin = 2.4V
VImax = ±25V
Transmitted data
47 GND
-
0V
Ground connection
51 RTS
I
VILmax = 0.6V
VIHmin = 2.4V
VImax = ±25V
Request to send
50
CTS
O
Min ±5V
Clear to send
52 RI
O
Optocoupled
Open collector
Ring indicator 35V max / 80mA max
