Technical Manual
Table Of Contents
3. ELECTRICAL DESCRIPTION
18
LZT 123 7607 R1B
3.2.4 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 230.4kbps (byte-oriented flow
control mechanism).
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Used to condition the GT47 for data transmission. The default level is
inactive by internal pull down.
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 high to enable transmission from the
GT47.
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CTS indicates that the GT47 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.
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DTR indicates that the DTE is ready to send and receive data. It also acts
as a hardware ‘hang-up’, terminating calls when switched low. The signal
is active high. You can define the exact behaviour of DTR with an AT
command.
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An active DSR signal is sent from the GT47 to the application (DTE) to
confirm that a communications path has been established. DSR has two
modes of operation, use the AT command AT&S to set the mode.
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DCD indicates that the GT47 is receiving a valid carrier (data signal) when
high. You can define the exact behaviour of DCD with an AT command.
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RI indicates that a ringing signal is being received by the GT47 when
high. You can define the exact behaviour or RI with an AT command.