
MIX Modem - GSM
User Manual V.1.1
Pag. 20
Subject to change without prior notice
MTX-63I/65I 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-63I/65I Terminal
• Port RxD @ application receives data from RXD of MTX-63I/65I Terminal
The RS-232 interface is implemented as a serial asynchronous transmitter and receiver conforming to
ITU-T V.24 Interchange Circuits DCE. It is configured for 8 data bits, no parity and 1 stop bit and can
be operated at fixed bit rates from 300bps to 460,800bps.
Autobauding supports bit rates from 1,2bps to 460,800bps. Hardware handshake using the /RTS and
/CTS signals and XON/XOFF software flow control are supported.
In addition the modem control signals DTR, DSR, DCD and RING are available. The MODEM control
signal RING (Ring Indication) can be used to indicate, to the cellular device application, that a call or
Unsolicited Result Code (URC) is received.
The electrical characteristics of the serial port signals are shown below:
Note: Outputs at 3kOhm load
Pin Signal Dir
Voltage
levels
Description
1
DCD
O
Min
±5V
Data carrier detect
2
RD 0
O
Min
±5V
Received data
3
TD 0
I
VILmax = 0.6V
VIHmin = 2.4V
VImax = ±25V
Transmitted data
4
DTR
I
VILmax = 0.6V
VIHmin = 2.4V
VImax = ±25V
Data terminal ready
5
GND
-
0V
Ground connection
6
DSR
O
Min
±5V
Data set ready
7
RTS
I
VILmax = 0.6V
VIHmin = 2.4V
VImax = ±25V
Request to send
8
CTS
O
Min
±5V
Clear to send
9
RI
O
Min
±5V
Ring indicator