5.7 Master Output and Channel Pass Through
The VCM-88(E) can be used as an eight-in/one- out remote level control for personal monitor mixing using the Master Output. Multiple VCM-88(E) units can be daisy chained to produce several unique mixes from the same program source. To simplify cabling for this application, the VCM-88(E) has the ability to internally pass each channel’s input signal directly to its output jack, disabling that channel’s direct VCA output but eliminating the need for special “Y” cables. The passed-through channel’s VCA output is automatically summed to the 200 Ohm pseudo- balanced Master Output along with other channels for fi- nal output. The gain from any one input channel to Master Output is -6dB so that a mix of several audio channels will have approximately the same volume as one of the input channels. See section 8.2 for channel pass-through details.
5.8 DC Control
A 15 pin female D-Sub connector on the back panel (12-position Euroblock on the VCM-88E) is used for DC control of the eight VCA channels and Master Attenuation, providing a simple and cost-effective method for custom control of the VCM-88(E). Most electronics hardware stores will have the male connector complement. The ref- erence DC voltage is also provided, thus requiring only the male connector, wire, and a 10K ohm potentiometer for each channel to control audio levels from any reasonable distance. See section 9.3 for DC Control details.
5.9 Remote Control Data Input
This connector is used for remote control by the Ashly RD-8 or RW-8, or other third party controllers. AMX and Crestron are companies which manufacture touch- screen computer interfaces for a variety of control applica- tions, including the VCM-88(E). AMX and Crestron pro- vide a hardware interface which uses the XLR Data In con-
nector on the VCM-88 and the Remote RD/RW-8 Euroblock connector on the VCM-88E. See section 9.1 for AMX and Crestron interface details.
5.10 Device ID Select
Each VCM-88(E) can be addressed to one of 16 devices, allowing for control of up to 128 channels (16 x 8) from a single data line. The device ID on the VCM-88E is selected in binary format from the Device ID DIP switch on the rear panel. The device ID on the VCM-88 is inter- nally selected with jumpers. See section 9.5 for Device ID Select DIP switch settings or internal jumper locations.
5.11 RS-232 Input
RS-232 is a bi-directional serial communications connection which allows computer devices to control other hardware. Ashly Protea System Software (see section 9.4) uses RS-232 to control the VCM-88(E), and other third party sources may use RS-232 as well.
While both the VCM-88 and the VCM-88E have dedicated RS-232 input jacks, only the VCM-88E RS-232 input is truly bidirectional. RS-232 data is read into the memory of the VCM-88E and stored, then read back from memory to get an actual snapshot of the current data set- tings. This is especially useful to upload to Protea System Software the current settings of a VCM-88E.
The VCM-88 data is unidirectional in receiving data only, meaning there is no RS-232 data out from the unit.
5.12 RS-232 Mode Switch (VCM-88E only)
The RS-232 mode switch is pushed in only when the VCM-88E RS-232 Input is connected to a PC, and an- other unit is connected to the Slave Data connector.
