Тһе SB-412A is designed for applications in which а person needs to communicate with up to four other people or groups of people and be able to quickly change any remote station's channel assignment from the front panel. The SB-412A's four main intercom channels can be accessed either individually or simultaneously, while still maintaining isolation between channels.
Access to the four main channels is controlled by the row of pushbutton and toggle switches along the bottom right side of the front panel. Separate controls for talk and listen for each channel enhance the station's versatility. The twelve switchboard inputs are individually assigned to опе of the four main channels or to an isolated OFF position, via the matrix switches on the left half of the front panel.
Controls which affect the input and output at the station (mic, headsets, speaker, and program) are located in a row along the upper right of the front
panel. Controls that are recessed be- hind the front panel are normally used only during installation and set-up.
The SB-412A is self-powered, and сап also power up to 20 speaker stations or 100 headset stations. it is normally used as a main station (which provides system termination at a central location), but may be used also as a remote station that provides extra power capacity.
On the SB-412A rear panel, опе XLR connector for each of the four channels
and the twelve switchboard inputs allows easy connection to the rest of the system. А program (auxiliary) input on the rear panel allows an external program to be monitored at the station and/or sent on one (or more) of the intercom channels. Its preamp gain is switchable for тіс- or line-level inputs. An external speaker jack is also provided.
Special functions, allowing 150 and IFB, may be set up with internal jumpers. See Section 111 for a detailed discussion of all controls and jumpers.