Specifications

2. Connect the FSK lines from the PK-900 to your radio's FSK or
RTTY input in accordance with your radio's requirements.
See Figure 3-4 below.
Figure 3-4 FSK Connector Connections
NOTE: When using FSK, the same power and duty cycle limits apply
as cited earlier for AFSK operation. Consult your radio's
operating manual for any power or transmit time limits.
3.4 PK-900 Configuration Jumpers and Connections
Before operating the PK-900, you must first make sure it is
correctly configured for your radio's PTT. After this has been
checked you should then connect the cables you constructed above.
3.4.1 Push-To-Talk (PTT) Configuration
Before you connect the radio cable(s) you just made to the
PK-900, consult your transceiver's manual for Push-To-Talk keying
polarity. Most transmitters and transceivers made in the last 15
years use Positive PTT keying. However some gear, especially if it
contains vacuum tubes, may use a negative PTT keying voltage.
The PK-900 is configured for positive PTT at the factory so it will
operate with most equipment without changes. However, if necessary,
you can change the polarity of the PTT configuration on either Port 1
or Port 2. Follow these steps:
o Remove four screws from the top of the PK-900 chassis cover and
lift off the cover.
o Locate Jumper posts JMP1 and JMP2 which are about 4 inches in
from the right-rear corner of the PCB.
o JMP1 configures Port 2 and JMP2 configures Port 1.
o When the shorting jumpers are towards the fuse, the port is
configured for Positive (+) PTT. When the shorting jumpers are
towards the center, the port is configured for Negative (-) PTT.
Replace the cover and four screws when you are finished configuring
the polarity of the PK-900 PTT circuit.
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