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tf-xhost.doc
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1995-04-01
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28 lines
de DG9EP @ DB0IZ.#NRW.DEU.EU
to IW2GKO @ IW2GKO.ITA.EU
EXTENDED HOSTMODE COMMAND by DG3DBI
The main purpose of the XHOST-Mode is the reduction of unnessecary
polling of the TNC and so an increment of speed on the seriell line.
There are only very few changes necessary in existing Hostmode-Terminal-
programs. E.g. GP support this mode.
The PC transmit the 'G'-Kommando to channel 255 of the TNC
An old-fashioned TNC without XHOST will answer with the errormessage
"INVALID CHANNEL NUMBER".
A TNC using the Extended Hostmode will transmit a nul-terminated string
(ASCIIZ) back to the PC. This string contains a list of channel
which have already some kind of Info in the buffer. This is also true
for the Monitor-channel (channel 0) and the statusinformation (Statusdaten).
The channelnumber inside the string are incremented by one, since the
null-terminated string wouldn't allow data of channel 0 otherwise.
Example for the answer of the TNC:
0xFF 0x01 0x00 - No Data available.
0xFF 0x01 0x01 0x00 - Some Data are waiting in the Monitor-Buffer.
0xFF 0x01 0x01 0x03 0x04 0x00 - Data in Monitor and channel 2 and 3
regards, Walter