Sony Ericsson TT4031 (SE-GM29) - Manual (Page 35)

Owner’s Manual Rev 1.0 Page 35 of 35
2.5.1 Serial Data
The modem supports the standard data character format of 1 start bit, 8 bit
data, no parity plus 1 stop bit, in total 10 bits per character.
2.5.2 Serial Data Signals - RD, TD
The default baud rate is 9.6 kbps, however higher bit rates up to 460 kbps
are supported. At start-up the TT4031 (SE-GM29) transmits and receives
data at the default rate of 9.6 kbps in either standard AT mode or binary
mode (the first received data - AT or binary format - determines the
operating mode). When reprogramming, the transmission rate is
automatically negotiated by the programming application. Speeds up to
460 kbps are supported.
Serial Data From Modem (RD)
RD is an output signal that the modem uses to send data to the application.
Serial Data To Modem (TD)
TD is an input signal, used by the application to send data to the modem.
2.5.3 Control Signals - RTS, CTS, DTR, DSR, DCD, RI
RTS and CTS are capable of transmitting at 1/10 th of the data
transmission speed for data rates up to 460 kbps (byteoriented flow control
mechanism).
Request to Send (RTS)
Used to condition the DCE for data transmission. The default level is high
by internal pull up.
The exact behaviour of RTS is defined by an AT command. Software or
hardware control can be selected. Hardware flow is the default control.
The application must pull RTS low to communicate with the modem. The
modem will respond by asserting CTS low, indicating it is ready for
communication.
Clear To Send (CTS)
CTS indicates that the DCE is ready to transmit data. The default level is
high. You can define the exact behaviour of CTS through an AT command,
and can select software or hardware flow control.