Kantronics MT1200, User Manual

Page: 91 / 157

CD {INTERNAL | EXTERNAL | SOFTWARE}
default INTERNAL
The CD command selects which carrier detect method will be used.
When set to INTERNAL, the TNC will detect a signal present on the channel, using an
energy type carrier detect, allowing shared voice and data on the same channel. Any
receive audio will trigger carrier detect.
When set to EXTERNAL, a signal is supplied by an external device, through the XCD
pin on the radio port, to indicate that a receive signal is present.
If set to SOFTWARE, the firmware inside the TNC will detect the presence of received
packet data to enable the carrier detection, allowing operation with un-squelched audio.
Correct operation of SOFTWARE carrier detect is affected by proper equalization and
the SWP parameter. If your RCV light flickers while receiving a packet, this is an
indication that you may need to adjust the equalization. (Equalization is set with an
internal jumper.)
When CD is set to INTERNAL or SOFTWARE, the external carrier detect pin on the
radio connector (if wired) can be used to hold off the TNC from keying the radio.
See also: SWP
CDINVERT {ON | OFF}
default OFF
Sets the sense of the XCD input. When set to OFF, a low input (near ground) is
expected to indicate a busy channel. When set to ON, expects a high (above 2 volts) to
indicate a busy channel.
CHECK n (n = 0 - 255)
default 0
The value entered for “n” is the number of 10 second intervals to wait during “no activity”
before making a periodic check (poll) to determine that a connected state still exists.
This “timeout” command is used to prevent a “hang-up” in a connected mode when a
link failure occurs as a result of conditions beyond control of the connected stations.
If n equals 0, this “timeout” function is disabled. While using Version 1 (AX25L2V2
OFF), a check timeout will initiate a disconnect.
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