Data Carrier Detected (Dcd; Ring Indicator (Ri - Telebit T3000 Reference Manual

response to the ring indicator to tell the modem to
answer the call. The DTR signal may be turned ON
when the DTE is ready to transfer data over the
interface, or simply used to indicate that the DTE has
been turned on.
You can configure the modem to interpret the DTR
in different ways, thus allowing it
to
interface with a
variety of DTE devices·that may use DTR
differently.
The modem uses Pin
6
(Data Set Ready) to indicate
its readiness to transmit or receive data. Data Set is
another term for modem, typically used by the Bell
Operating Companies.
Data Carrier Detected (DCD)
Although this signal line is actually named Received
Line Signal Detector in the RS-232D standard, the
term Data Carrier Detected (DCD) is more
commonly used. When pin 8 (Data Carrier Detected)
is active (DCD is ON), the DTE recognizes that the
modem has received a signal over the telephone
network, which meets its criteria for an acceptable
carrier signal.
Depending on the requirements of the DTE device,
you can configure the modem to hold DCD ON
whether or not a carrier is detected, or to turn DCD
ON only when an acceptable carrier signal is
detected.
Ring Indicator (RI)
The modem uses Pin 22 (Ring Indicator) to inform
the DTE that the telephone is ringing. The Ring
Indicator (RI) signal goes ON in cadence with the
B-1 O Interface Description