[Date Prev][Date Next][Thread Prev][Thread Next] - [Date Index][Thread Index][Author Index]

Re: Using WISP with TNC3S - config KISS?

> ... I need help with is setting up WISP to use the TNC3S from Symek.
> My TNC3S has a 1200 baud modem on port one ... port 2 is 9600 baud
> modem for the satellites that needs to be switched into the KISS mode
> for use with WISP.

Let's assume, RSKISS.apl runs on the TNC3. All received data from
both modems is sent to the PC as KISS packets including the 'port'
nibble set to "0" for those packets received by port 1 and set to
"1" for the packets received by port 2. As WISP ignores this
information, data from both ports is treated equal and processed
by WISP. This about RECEIVING with TNC3 and WISP.

When you want to transmit with TNC3S (RSKISS), you have to adress
the port with every KISS packet to tell the TNC3, which port should
be used for transmission of this packet.

As far as I know, WISP has this adress fixed set to "0". So,
transmission via Port 2 is not possible until WISP allows more
flexible adressing of multiport TNC.

Usually, the TNC3 is equipped with a 9600 baud modem on port1 and
a 38400 baud modem on port2. With this combination, you can receive
sat data with 9600 or 38400 and transmission is always done with 9600.

To use a 1200 AFSK / 9600 FSK TNC3 for satellite in KISS mode, you
should just swap the modems to have 9600 on port 1 and 1200 on port 2.

WISP will have no problem as port 1 is its default setting.

The question is, which mode (hostmode or KISS) you use with the
1200 baud APRS. If APRS uses KISS but doesn't support multiport
TNC, there will be the same problem as before.

Note: the oroginal KISS protocol specification by Phil Karn, KA9Q in
August 1986 defines the upper nibble of the command byte as the
port address. So, TNC with up to 16 ports can be controlled.
The SMACK enhancment of KISS adds a checksum to the KISS packets
and uses the MSB of the command byte to distinguish KISS and SMACK
packets. So, with SMACK, you can still control TNC with up to 8 ports.
As all TNC before TNC3 had one port only, the 'multiport feature'
of KISS has fallen into oblivion but should be used with all new
KISS concepts to take advantage from the modern multiport TNC.

> My understanding is if I make these files and place them into the
> directory WISP will use them to switch the TNC into the KISS mode only
> during a pass and when the pass is over, switch back to normal.

Adressing of port 1 / port 2 cannot be done permanently by some
setting but must be done with every single packet using the port-
adress nibble of command byte.

> Anybody have some samples of these files? I have not been able to find any
> information on how to go from the KISS mode back to another mode.

73! Ulf, DK9SJ@qsl.net 

Via the amsat-bb mailing list at AMSAT.ORG courtesy of AMSAT-NA.
To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org