Meilhaus Electronic ME-90 Series, Electronic Manual

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to send data. The procedure is reversed when switching from
transmit to receive.
DSR (Data Set Ready): This is also called DCE Ready. In the answer
mode, the answer tone and the Data Set Ready are asserted two
seconds after the telephone goes off hook.
GND (Signal Ground): This is the common return line for the data
Transmit and Receive signals. The connection between the two
ends is always made.
DCD (Data Carrier Detect): This is also called the Received Line
Signal Detector. It is asserted by the modem when it receives a
remote carrier and remains asserted for the duration of the link.
DTR (Data Terminal Ready): This line enables, but does not cause,
the modem to switch onto the line. In originate mode, Data
Terminal Ready must be asserted in order to auto dial. In answer
mode, Data Terminal Ready must be asserted to auto answer.
RI (Ring Indicator): This pin is asserted during a ring on the line.
Note: Keep the signal levels (see appendix “A Specification”).
3.7.2 The RS-422/485 Standard
In comparison to the RS-232 standard the RS-422 and RS-485
standard allow reliable data transfer over greater distances. For
optimum noise immunity twisted pair wires will be used. The data