Timewave DSP-232, Руководство по эксплуатации

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Chapter 12 PACTOR Operation
PTCONN starts the PACTOR connect protocol. To start a PACTOR connect, type PTC followed by the other
station’s callsign. Example:
cmd:
PTC WF7A
As soon as (
RETURN
) is pressed, the DSP will key your transmitter on and off with the PACTOR connect
sequence. If you’re connecting with a station by long path (more than halfway
around the world), use an exclamation mark before the callsign:
PTC !WF7A
This changes the PACTOR timing to allow for the extended radio propagation time.
PTHUFF
n Default: 0
Mode: PACTOR Host:PH
“n” 0 to 3, specifying a type of compression that may be used in PACTOR.
To enhance the effective data rate in PACTOR, a data compression scheme (called Huffman) may be automatically
enabled.
0
No compression (default)
1 Huffman encoding.
2
,
3
Presently not implemented but reserved for future use.
Instead of using the normal 8-bit ASCII representation of a character, Huffman encoding assigns each character a
code that may be as few as 2 bits—for the most-used characters—to as long as 15 bits for the least-used characters.
For English (and most other) languages, the use of Huffman compression results in a smaller number of bits
necessary for a given message. For messages consisting of non-text information such as computer programs,
Huffman compression would need more bits than ASCII and would be less efficient.
If
PTH is OFF , PACTOR will never use Huffman compression. With PTH ON , Huffman compression will be used
if it is more effective. Don’t use Huffman compression with binary file transfers as it only works with 7-bit data.
PTList Immediate Command
Mode: PACTOR Host: PN
PTList
switches your DSP into the PACTOR listen mode.
In PACTOR Listen (and
ALIST ) modes, monitored connect attempts are displayed like this:
>W1AW <C>
The callsigns are shown one per line and are meant to resemble the way the TNC monitors connect frames in the
packet mode. Since neither mode supports identification within the calling blocks, no source callsign can be shown.
You can usually monitor a PACTOR contact between two connected stations using
PTLIST
. Since your station
isn’t part of the error-free link, if the CRC check doesn’t produce a correct check sum nothing will be displayed on
your screen. If the receiving station requests a repeat and you’ve copied the packet without errors, the message
won’t print twice.
PTOver n Default: CTRL-Z ($1A)
Mode: PACTOR Host:PV
“n” A hexadecimal value from $00 to $7F used to select the change-over character used in linked PACTOR.
12-18 September, 05