16
Using single-ended amplifiers
If your power amplifier does not have balanced inputs, the adapter used
to convert from balanced to single-ended must “float” Pin 3 (the inverted
signal). This can easily be checked with an ohmmeter: the impedance be-
tween Pin 3 and either the center pin or the shield skirt on the RCA should
be infinite. Tying the output of Pin 3 to ground (as some adapters do) will
compromise the performance of the SC-1. Should you need them, prop-
erly wired adapters are available from Wisdom Audio for an additional
charge, or they can be purchased online at
http://www.markertek.com/Connectors-Adapters/Audio-Adapters/XLR-to-
RCA-Adapters/Switchcraft-Corporation/322X.xhtml.
5
USB Port
This USB port is used by your installer to connect a Windows-compatible
PC for setup and calibration. It provides two-way communication between
the SC-1 and the computer that is used for adjusting the many parameters
of the system controller.
6
RS232 Interface
The RS232 interface allows an external control system such as AMX, Con-
trol4, Crestron, or Savant to control the SC-1. All basic operational modes
are supported (operate, standby, selecting setup memories).
When the SC-1 is first powered up, it will identify itself to the control
system via the RS-232 port, sending either
Wisdom Audio SC-1
or
Wisdom Audio SC-1
Ready...
ERROR
…depending on whether there is at least one setup memory that has been
calibrated and is available for use. (For proper operation, at least one setup
memory must be saved into the SC-1’s non-volatile memory.)
The RS232 port is wired as a DCE, and connects via a straight cable to a
DTE, or via a null modem/crossover cable to another DCE (uncommon).
•
Pin 2 is the TRANSMIT for data FROM the SC-1 TO the control
system, and carries RS232 signal name RxD
•
Pin 3 is the RECEIVE for data FROM the control system TO the
SC-1, and carries RS232 signal name TxD
•
Pin 5 is the GROUND/COMMON for the pin 2 and pin 3 sig-
nals
The other pins are not connected, the shell is grounded at the same point
as pin 5. Signal names RxD and TxD are named from the point of view of
the DTE and that’s why the names appear to be backward but are not per
the standard.
Off the shelf USB->RS232 adapters plug right in to the port and work as
expected without special configuration.
The commands available to your control system programmer are as fol-
lows: