7K • Appendix C
C-12
Repeater Transmitter PTT section on page C-5 for details on the design of the
output circuit.
The power MOSFETS used as logic output drivers appear as 5Ω resistances to
ground when in the conducting state (ON), and can sink up to 75mA. They
appear as open circuits when in the non-conducting state (OFF). Do not apply
over 40VDC, as the transient suppressors start conducting at 40V.
Since the drain connections of the MOSFETs are brought out to the connector
without pullup resistors, this configuration is called open drain (similar to open
collector circuits using bipolar transistors). An ohmmeter cannot be used to
check the logic outputs, since no change will be seen when the outputs are
turned ON and OFF. A DC power source and a load of some type will be
needed to see the outputs change state. If you need TLL- Compatible Outputs,
simply connect pullup resistors of 3KΩ from the desired outputs to the 5V
power supply of the TTL device being driven.
Logic outputs are very handy for controlling external devices and appliances at
the site. Loads include incandescent lamps, LEDs, integrated or discrete logic,
and relay coils.
Note: Although the power MOSFETS are protected by transient suppressors in
the controller, it is still important to wire diodes across inductive loads (such as
relays) in the non-conducting direction.
Each logic output may be commanded to be Latched ON or OFF, or
Momentary turned ON or OFF for 0.5 seconds.
The controller will remember the status of each logic output during power
outages. When power returns, the controller will turn the outputs ON or OFF to
match the conditions before the power loss. An initialization sequence will force
all outputs OFF.
Telephone Line Connection
If your controller is equipped with the Telephone Interface Module, you can
connect the controller to the telephone network. The 14-foot cable supplied
with your controller has a modular USOC (Universal Service Order Code) plug
at each end. This plug mates with the USOC RJ11C jack. Connect one end of
the cable to the controller, and the other end to the RJ11C jack at your
repeater site.
The Telephone Interface Module is registered under Part 68 of the FCC Rules
and Regulations for direct connection to the telephone line. A label is attached
on the rear of the cabinet, listing the registered number and ringer equivalence.
It reads:
Complies with Part 68, FCC Rules
FCC Registration No. GHZ37K-10180-DP-N
Ringer Equivalence: 1.3B
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