Contemporary Research 232-STSI, Product Manual

Page: 12 / 20

Contemporary Research 12
232-STSi PAL TV Tuner
RS-232 Control – General Commands
XX Mute A/V off Turn A/V outputs on at previous level
XM Mute A/V on
Example: ‘>XM’
Mutes A/V outputs
Mutes audio and video outputs
P0 Power Off Same as XM
P1 Power On Same as XX
PT Power Toggle Same as XT
VU Ramp volume up Starts volume ramping up
VD Ramp volume down Starts volume ramping down
VL Ramps volume to level (0 – 63) Sets volume to specific level
VX Volume Mute off Restores audio volume to previous level
VV Stop volume ramp Stops volume ramping
VT Toggle Volume Mute Alternates audio mute on and off
VM Volume Mute on
Example: ‘
>VM’
Turns off audio outputs
Mutes audio outputs
A carriage return is required at the end of each command and is assumed in all examples. The ‘=’
sign for parameters may be omitted if desired, though it is helpful for clarity in checking
programming.
Working with A/V Detectors and Status
The 232-STSi has two active A/V sensors, the audio sensor detects if the station in broadcasting in stereo or mono,
and the video sensor looks for presence of video. If you desire, your control system can respond whenever the status
of the audio or video detectors change. For example, you can change the text of a button to MONO or STEREO by
tracking the Audio Status Response (V), shown on page 13. In the same way, you can light up a NO VIDEO button,
when the Channel/Source Response (T) indicates a video loss.
If you use AV detector status, it’s important to understand how the functions will operate in the real world. When you
change from a stereo channel to a mono broadcast, the V string will first show the audio status as stereo. When the
audio detector locks in, the status will be sent again, indicating mono audio. This is similar to the stereo/mono
indicator and “blue screen” functions on your TV, there may be a little delay, and the function may switch back and
forth a couple times for marginal stations. So expect that the detectors may send the string a few times as well.
As most applications aren’t tracking the A/V sensors, the tuner is normally set not to send a response string whenever
the detectors sense a change. You can turn on one or both functions using the Q3 command on page 9.