9 Packet-Radio
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Chapter 9
9 Packet-Radio
The Packet-Radio-menu (pac:-menu) is activated with the command PACket. The
command prompt takes the form pac: .
The following commands are available in the pac:-menu:
Aprs, Baud, CBell, CHeck, CMsg, Connect, CONStamp, CONVerse,
CStatus, CText, DIGIpeat, Disconnect, FRack, Help, JHOST1,
KISS, MAXframe, MCon, MFIlter, Monitor, MStamp, MText,
MYAlias, MYcall, MYMail, PACLen, PErsist, PRBox, Quit,
RESptime, RETry, Setchn, SLottime, TRACE, TXdelay, TXLevel,
Unproto, USers.
All other (normal) commands are not available in the pac:-menu! Quit or DD exit the
pac:-menu.
The PACket command can be followed by a valid pac:-command as an argument. As
with the other sub functions of the PTC-IIIusb, it is also possible to pass through direct
commands.
Switch off the Packet-Radio listen – without using the pac:-menu
cmd: PAC M 0 <Return>
9.1 DAMA
The PTC-IIIusb in Packet-Radio is full compatible with the DAMA (Demand Assigned
Multiple Access) standard. You easily recognize a DAMA-Digi with a look to your
monitor. The expression [DAMA] is added to the header of the monitored packets, if the
packet is received by a DAMA-Digi. The DAMA mode needs not be activated by the
user. The PTC-IIIusb automatically notices if you are working with a DAMA-Digi or not
and behaves respectively.
9.2 Modern Times
We hope you have already recognized the following warning:
The PTC-IIIusb expects all time parameters in milliseconds!
The settings of the time parameters are very important for proper Packet-radio operation!
How long to wait for the confirmation (FRack). How long is the time until it is checked
if the other station is still available (CHeck), etc. The function and most of all the
reliability of a Packet-Radio connection depends on the time parameters.
Because of this, check the initialization files of programs you use in advance and very
carefully. Often the added examples are designed for a TNC 2. But the TNC 2 expects the
time inputs in 10 ms steps, e.g. for a TxDelay of 100 ms the value 10 has to be given for
a TNC 2! But the PTC-IIIusb needs the value in milliseconds, that means 100.
If you use the initialization files without checking, it could happen, that the very
important timing data becomes 10 times too low.
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