Technical data

www.westermo.com Theoretical and general applications 27
Key to the most important signals
Explanation of the most important signals
GND Protective Ground Pin no. 1 is reserved for protective ground
between the devices.
SG Signal Ground Signal ground is a signal reference and must
always be connected to pin 7 (25-pin)
pin 5 (9-pin) in V.24.
TD Transmitted Data This signal transmits data from a DTE to a DCE.
RD Received Data This signal is the data that a modem or a DCE
transmits to a DTE.
RTS Request to Send This signal is a request to send data from a DTE.
The device waits for the CTS answer signal.
CTS Clear to Send The answer signal from DCE which tells the DTE
that it can transmit data.
DSR Data Set Ready The signal from a DCE which indicates that the
device is switched on, connected and ready.
DTR Data Terminal Ready The same as DSR, but from a DTE.
DCD Data Carrier Detect The output signal from a DCE which indicates that
there is a carrier between the DCEs and that the
connection is ready for communication.
EC External Clock This signal is used in synchronous transmission
when it is necessary to clock data. The signal is the
input into the DCE.
TC Transmit Clock Transmits the DCE clock in synchronous systems.
RC Receive Clock Clock received in the DTE for decoding data.
RI Ring Indicator Output signal from a modem indicating that it has
received a ring signal.
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