HD491 Smart Encoder
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All Rights Reserved.
Local Caption Entry
This section covers methods for inputting closed captioning data into your
491 Encoder using the serial ports or dial-up modem. The same commands
can for caption entry and settings can also be entered to the HD491 Web
Terminal
Data Port Settings
The serial data input ports (labeled ‘P2’ only for HD491) are factory
configured to use the RS232 protocol at 1200 baud, 7 data bits, and Odd
parity. To change these settings, see page 37. The dial-up modem is set
to operate at 2400 baud, but will also operate at 1200 baud without
explicit reconfiguration.
The Encoder controls the flow of data from input ports to the processing
queue using XON/XOFF handshaking protocol. XOFF will be sent when
the queue is over ¾ full. When the queue clears to ¼ full, XON will be
sent. The XON and XOFF characters are sent with a parity bit determined
by the parity setting of the port they are sent through. Hardware
handshaking is not supported and must be disabled when connecting the
Encoder.
To communicate through the serial data ports, connect the port to a PC
serial port with a standard 9-pin connector, and begin entering data
through a serial communications application such as HyperTerminal on
Windows. If you have trouble communicating using HyperTerminal,
always check to make sure that the settings in the Port Settings menu in
HyperTerminal match the settings for the Encoder port you are connected
to.
Smart Encoder Command Format
The 491-series Encoders maintain full compatibility with the industry
standard EEG Smart Encoder command set for closed caption data entry.
All Smart Encoder control commands begin with a leading control code
of <CTRL+A>, also represented by the ASCII hex code 01. A Smart
Encoder control command must end with a carriage return; use the
<ENTER> key on a keyboard or 0D in ASCII hex. Note that both the
<CTRL+A> and <ENTER> characters are usually non-printing in serial
port communication programs.
