Kantronics KPC-2 - Page 39

Watch Dog Timers
Jumpers are appropriately labeled on the PC board. Refer to the parts location
diagram for help in locating them. Also refer to the Assembly and Disassembly section
for information on obtaining access to the interior of the TNC.
KAM - VHF Timer - Jumper K3
This jumper is provided to disable the VHF watch dog timer. The timer is disabled
if the jumper is installed. Time-out of the KAM will occur after approximately 2.5
minutes, un-keying the VHF PTT line. The KAM is shipped with the jumper not
connecting the jumper posts; therefore, the timer is in effect.
KAM- HF Timer - Jumper K4
This jumper is provided to disable the HF watch dog timer. The timer is disabled if the
jumper is installed. Time-out of the KAM will occur after approximately 2.5 minutes,
un-keying the HF PTT line. The KAM is shipped with the jumper installed; therefore,
the timer is not in effect.
KAM Operating Note
As shipped from the factory, the VHF watch dog timer is in effect and the HF watch
dog timer is not. The HF timer is not enabled since it cannot distinguish between
RTTY and Packet signals. Should you plan to operate a mode other than Packet the
HF timer will limit your transmission time to approximately 2.5 minutes if it is
enabled.
P KPC-4 - Timers - Jumpers K5 (Port 1) and K6 (Port 2)
These jumpers are provided to disable the watch dog timers. The timer is disabled if
the jumper is installed. Time-out of the KPC-4 will occur after approximately 2.5
minutes, un-keying the PTT line. The KPC-4 is shipped with the jumpers not
connecting the jumper posts; therefore, the timers are in effect. Should you wish to
have a SHORTER timer interval, it may be obtained by changing the appropriate
resistor shown in the following chart.
K5 K6
Port 1 Port 2 Time Delay Resistor Value
R43 R44 1.25 min 470 Kohm
R43 R44 .75 min 220 Kohm
R43 R44 .5 min 2.2 Mohm
P
.
²
m
WATCH
DOG
TIMERS
33
O Copyright 1989, Kantronics, Inc. All Rights Reserved. `
Duplication of this manual or the firmware without Version 2.85
permission of Kantronics, Inc. is prohibited. Installation Manual
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