Telebit WorldBlazer User Manual page 57

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-232 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 tum DCD on only when an
acceptable carrier signal is detected.
Ring Indicator (RI)
8-6
The modem uses pin 22 (ring indicator) to inform the
DTE that the telephone is ringing. The RI signal goes on
in cadence with the ringing signal on the telephone line.
When the ringing voltage is present, RI is active. Between
rings, RI is off.
You can configure the modem can be configured to
answer an incoming call automatically or to answer the
call only when the DTE indicates that it is ready to accept
the call by turning DTR on.
Interface Description 90257-01