Orban OPTIMOD-FM 8700, Operating Manual

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2-4
INSTALLATION ORBAN MODEL 8700i
Figure 2-2: Wiring the 25-pin Remote Interface Connector
6. Connect tally outputs (optional)
See the schematic on page 6-42.
There are two tally outputs, which are NPN open-collector and operate with re-
spect to pin 1 (common). Therefore, the voltage applied to the load (such as a re-
lay or optoisolator) must be positive. You can use the 12 VDC source on pin 25 to
drive the high side of the load, taking into account the fact that the voltage on
pin 25 is current limited by a 310
Ω
resistor.
The tally outputs are protected against reverse polarity.
I
To avoid damaging the 8700i, limit the current into a tally output
to 30 mA. DO NOT connect a tally output directly to a low-
impedance voltage source! The tally outputs are not protected
against this abuse and Q3 or Q4 is likely to burn out.
Note that the tally outputs have no special RFI protection. Therefore, it is wise to
use shielded cable to make connections to them.
See Tally Output Programming on page 2-63 for instructions on using the tally
outputs.
7. Connect to a computer
You can connect to a computer via the 8700i’s serial connector or via an Ethernet
network. (See
Networking on page 2-63.)