Timewave PK-900, Operating Manual

Page: 149 / 392

9.6.3 Inverting Black and White (FAXNEG)
You may occasionally come across a station that appears to be
inverted; that is displaying black where you expect white, and leaving
white where you expect black. In this case you may issue the command
FAXNEG ON. The PK-900 will respond with:
FAXNeg now ON
What was before displaying black will now be white, and vice versa.
9.6.4 Display Density (GRAPHICS)
How the graphics will look on your display depends on the setting of
the GRAPHICS command. There are 7 graphics commands providing
horizontal dot densities from 480 dots to 1,920 dots horizontally
across a page. The default setting is 960. See the GRAPHICS command
description in the Command Summary for a complete description of
this command.
9.7 Displaying Other Services
Most of the weather services in the US use a facsimile scan speed of
2 lines per second, which corresponds to FSPEED 2 (Default).
Facsimile photographs often use 1 line per second, which is FSPEED 1.
Some foreign services use speeds of 4 lines per second, which is
FSPEED 4. Speeds of 1.5 and 3 lines per second are also supported.
See the command summary for more information on FSPEED.
When different horizontal scan speeds are used, the number of lines
per vertical inch can also vary. If nothing is done to change the
number of lines displayed, the pictures may appear squashed or
elongated. The ASPECT command resolves this by allowing from one to
six lines to be displayed out for every six lines received. The
default setting is ASPECT 2 which means that 2 out of 6, or 1 out
of every 3 horizontal lines is displayed. This is the most common
setting you will use for WEFAX, but other services may require using
other values to display pictures without aspect ratio distortions.
9.7.1 The PK-900 FAX Modem
The PK-900 uses a special modem (MODEM 8) for HF WEFAX operation.
This modem has a bandwidth of 800 Hz and a center frequency of 1900
Hz.
9.8 Transmitting FAX
The PK-900 does support FAX transmission, but attempting to do this
without an AEA's PC-PAKRATT II WITH FAX program is difficult. We
recommend you consider this program if FAX transmission is desired.
3/93 9-7