Museum Technology Source CC-1000 Closed Caption Displays - Manual (Page 2)

Introduction:
The CC-1000 and CC-2000 are Caption Display Boards that decode and display television
closed captions (CC) carried on Line 21 of the standard NTSC video signal. The text is dis-
played on four lines of green LEDs, each with 32 characters. The only difference between
the models is the size. For the CC-1000, the characters are .7 inch high, suitable for view-
ing at distances up to approximately 35 feet. The CC-2000 employs 1.2 inch characters,
suitable for viewing at a distance in the fifty to sixty foot range. Any differences (aside from
size) will be indicated by use of italics. Low voltage remote control screw terminals are pro-
vided to turn the display on and off, or to switch between normal captioning (CC-1) and
CC-3. CC-3 is typically used for a second language. With no connection to the remote ter-
minals, the display will be on, displaying normal CC-1 captions. Hence, for most applica In
order to blank the display, a switch connected to terminals 1 and 2 will cause the display to
switch to CC-3 mode. Provided that there is nothing on CC-3, which is usually the case,
the display will turn off. If, however, there is captioning on CC-3, it will be displayed. Note
that several seconds may elapse between when the switch is closed and the display turning
off. Likewise, when the switch is opened, there can be a delay while until a complete cap-
tion is received. This is to prevent the display from turning on in the middle of a captioning
stream, with the resultant display of a partial caption.
Connections:
Please refer to the attached drawing for connections and their function
Electrically, the CC Board is installed as if it were a standard TV monitor.
The video signal carrying the CC information connects to the CC-1000 using a BNC con-
nector. A second BNC connector is provided as a loop-through. The input is not terminated.
Although good practice, 75 ohm termination is not required in that the automatic gain con-
trol circuit in the CC- will operate correctly over a range of .5 to 2 volts.
The remote on/off function are accessed via a pluggable Euro-style terminal block.
Selection of CC-1 or CC-3 is also made at this terminal block. The default, with no connec-
tions, has the display on, and CC-1 (Normal) selected.
Terminals 3 and 4, when connected together will casue a test message to appear on the
display. This may be helpful in setting the brightness.
Power is provided by an external desk-top power supply which connects to the display with
an attached 2.1 mm plug. AC power input to the supply is made with the supplied IEC
power cord.
Installation:
Generally the CC- is mounted as close as possible to the bottom of the video screen.
Frequently it is mounted flush in a cut out in the exhibt surface, supported in the back on a
shelf or by brackets. To assist in mounting the CC-1000, six holes on both the top and bot-
tom are drilled and tapped to accept 8-32 screws. This is a common size for screw eyes,