8 FAX
8.7.8
PR300
This mode has been left available for compatibility purpose with the PTC-II. Much
more comfortable you operate 300 baud Packet-Radio using the
pac:-
menu. Refer to
.
300 Baud Packet operation is now possible with the PTC-IIex when using the program
TFX
in addition.
TFX
is started on the PC as a TSR program (memory resident) and
discretely operates the packet protocol in the background. The PTC-IIex itself operates as
a modulator/demodulator in this case, such as
BayCom
or
PC-COM
. The combination of
PTC-IIex and
TFX
emulates a
real
hostmode TNC for 300 baud Packet that can be
operated with a hostmode terminal program such as
GP
. The command
PR300
starts the
TFX
compatible 300 baud PR modem.
The LED´s are set to medium brightness, i.e. the
BRightness
parameter has no
function.
TFX
should be used with
hardware DCD
turned on. The MARK tone is the one also
valid for PACTOR and the SPACE tone is always located exactly 200 Hz below the
MARK tone.
The
TFX
program is available at nearly every Packet-Radio mailbox or in the internet at
http://www.nordlink.org
8.8
Transmission during MODEM operation
In every MODEM-operational mode, independent of if it is AM-FAX, FM-FAX, SSTV
or FSK, the PTC-IIex keys the transmitter (PTT becomes active) when it receives bytes
with a value between 0 and 63. The transmitter stays on for exactly 166.7 ms after
receiving each
transmit-byte
. If the PC program sends the transmit data appropriately fast,
then the transmitter stays in the transmit condition. If the data does not change within the
166.7 ms (for example when in FM-FAX only
white
must be transmitted), then the PC
program must send data to the PTC-IIex at least every 166.7 ms, so that the transmitter
stays on transmit. By using this system, an extra PTT-command is not required.
The maximum transmit amplitude is set using the
FSKAmpl
in the main menu. It is not
necessary for any new setting to be undertaken, and can be left at setting for PACTOR or
RTTY.
The PTC-IIex displays the present transmit data on the tuning indicator directly. The
left-
hand limit
represents the value 0, the
right-hand limit
63.
During the transmit operation, the appropriate demodulator operates unchanged (up to the
LED-display). The PTC-IIex always operates in the special modes as a FULL-DUPLEX
MODEM.
8.8.1
Transmission in AM-FAX-Modem mode
For transmit operation in AM-FAX a constant carrier tone of 2400 Hz is generated. The
transmit data controls the amplitude of this tone: The value 0 means the carrier tone
3
Be aware that Internet addresses frequently change
105
Содержание PTC-IIex
Страница 14: ...List of Figures and Tables XII...
Страница 30: ...3 Installation 16...
Страница 108: ...7 Audio 94...
Страница 126: ...8 FAX 112...
Страница 173: ...12 SYStest 159...
Страница 183: ...14 Circuit Description 169...
Страница 195: ...15 Basics 181...
Страница 201: ...B Technical Data 187...
Страница 202: ...C Layout Appendix C 19 Layout B 1 Motherboard Figure B 1 Motherboard 188...
Страница 203: ...C Layout 189...
Страница 215: ...Index 202...