PK-232 MBX – OPERATING MANUAL PACKET-RADIO
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4.8.9 Sharing Packet Channels with Voice Operation
Although it is seldom needed, the PK-232 does have an input for SQUELCH information
from a transceiver on the RADIO connectors. This input should be used and the SQUELCH
command set if the Packet channel is to be shared with voice operation.
4.8.10 Disabling Transmit Operation
Occasionally for test purposes it may be desired to disable the PTT circuit in the PK-232.
This can be done with the XMITOK Command.
4.8.11 The Packet QRA Feature
The PK-232 recognizes UI frames with a destination field of 'QRA" and will respond by
sending an ID packet. This is helpful for others new to your area that are looking for other
Packet stations to talk to. To disable this feature and remain anonymous, simply set user
BIT 22 OFF (UBIT-12 OFF). The default is ON.
If you wish to see who is available in your local area, simply set your UNPROTO path to
QRA and send a packet. Within 1 to 16 seconds otherstations should respond to your QRA
request by sending an ID packet of their own. This feature is compatible with TAPR's QRA
feature introduced in the 1.1.8 firmware release.
4.9 Seldom Used Commands
The following commands operate in Packet, but are seldom needed. They are listed for
reference and described in the Command Summary.
Afilter – BBsmsgs – ONPerm – CPactime – Dcdconn – Flow – HEAderln – MDMon – MRpt –
MXmit
4.10 Packet Lite HF Packet Protocol Extension
Amateur radio needs a better communications mode for HF operation. Baudot and ASCII
have no provision for error detection. AMTOR FEC and ARQ are more resistant to errors, but
do not carry the full ASCII character set. 300 baud AX.25 packet is undesirable because the
long transmissions are prone to bit errors, any one of which invalidate the whole frame.
Packet Lite is, as its name suggests, an abbreviated form of Packet. It is designed as a
transparent extension to the AX.25 protocol that reduces the "overhead" of all HF Packet
frames without digipeaters. Packet Lite does not solve HF Packets problems, but it should
provide some throughput improvement on HF where it is desperately needed.
Timewave’s engineering department is interested in hearing from Packet Lite users with any
comments or suggestions on improving the protocol.
A Brief Description of the Packet Lite Protocol
The main feature of Packet Lite that reduces overhead is that it uses an address field of only
4 bytes. A standard AX.25 header without digipeaters uses 14 bytes of addressing. Shorten-
ing the packet frame header lessens the possibility of any given frame taking a hit.
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