TS4000 Radio Modem User’s Manual
Serial Port
15
The RI (Ring Indicator) pin is pin 9 of a standard 9 pin subminiature D connector
and is an output for DCEs (the TS4000). The TS4000 has no internal RI signal
and therefore the RI pin is normally left unconnected.
RI Pin Signal Options
As an alternative, the RI pin can be connected as a power pin into the TS4000.
This is non-standard use of this pin and therefore care should be taken when
connecting the TS4000 to other serial devices. For most serial devices this is not
a problem because RI is a modem (DCE) output and the TS4000 power supply
mostly falls within the allowed voltage range for RS-232 signals. Therefore the
power voltage on this pin is interpreted as an active RI signal. For systems that
use the RI signal differently, or cannot operate with power on this pin, this pin
should be disconnected between the TS4000 and the host equipment.
RI for Modem Power
As an alternative, the RI pin can be connected to the internal DSR output signal.
RI Connected for DSR
The DSR (Data Set Ready) pin is pin 6 of a standard 9 pin subminiature D
connector and is an output for DCEs (the TS4000). For the TS4000, the DSR
pin is normally connected to the internal DSR output signal.
DSR Pin Signal
Options
As an alternative, the DSR pin can be set to always be in the active high state.
In this case it is internally connected to +5 volts through a 1 K
ohm
resistor.
DSR Always High
The DTR (Data Terminal Ready) pin is pin 4 of a standard 9 pin subminiature D
connector and is an input for DCEs (the TS4000). For the TS4000, the DTR pin
is normally connected to the internal DTR input signal.
DTR Pin Signal
Options
As an alternative, the DTR pin of serial port 1 can be connected as a power pin
into the TS4000. This option is only available for serial port 1.
DTR for Modem Power
Caution: The use of the DTR pin for power is non-standard. Therefore the
TS4000 serial port must not be connected to a standard serial device that
drives the DTR pin (i.e. a PC).
Connecting a TS4000, that is configured for
power through the DTR pin, to a device that drives the DTR pin can result in the
power supply voltage of the TS4000 being shorted to the DTR output of the host
serial port. This could damage to the host device.
Therefore, when connecting
the TS4000 to a PC for configuration, make sure that the cable does not have a
DTR (pin 4) connection.