S-COM 6K Owner's Manual page 18

7. RECEIVER #2 (CONTROL/LINK RECEIVER) COR
Your controller can be interfaced to a second receiver, if desired. This receiver can serve a number
of applications, depending on your needs. Paths can be "set up" or "knocked down" between
Receiver #2 and three devices: The transmitter, the DTMF decoder, and the phone line. Path
control is done by DTMF commands. Allow a path between RX2 and the transmitter, and you now
have a link receiver. Allow a path between RX2 and the DTMF decoder, and you now have a
control receiver.
If you decide to add a second receiver, the controller will require a COR signal from it. Feed the
COR into pin 5 of J2.
The controller's RX2 COR input circuitry is designed exactly like the RX1 COR input. The transistor
in this case is Q2D, the voltage divider is made up of R11C and the resistor on pin 5 of R12, and
the pullup resistor is R14. You may wish to refer back to the "RECEIVER #1 COR" section of this
manual for a discussion of the hardware design of the input circuit.
To check your Receiver #2 COR interface, power up the receiver and the controller. Measure the
voltage at pin 5 of J2. This voltage must swing above and below the 2.1 V threshold as the
incoming carrier is applied and removed.
You must also determine the "sense" of your receiver #2 COR output. Does the output go "low" or
"high" when a carrier is detected? If the output goes "low" when the carrier is detected and returns
"high" when the carrier is removed, then place dip switch #2 in the ON (closed) position. If,
however, the output goes "high" when the carrier is detected and returns "low" when the carrier is
removed, then place dip switch #2 in the OFF (open) position.
IMPORTANT: If you are not using a second receiver, be sure dip switch #2 is in the ON (closed)
position. This configures the RX2 COR input for a low-active COR signal. The pullup resistor on
this input will hold the input high, thus making sure the controller does not see activity on this input.
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6K V1.02 03-16-91