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This system uses the classic 'offer-accept' principle to connect up to three studios to a transmission path and provides facilities for sustaining services and delay systems. Multiple units can be cascaded to cater for larger installations.

This is a complex piece of equipment, designed to fulfill the requirements of a small stereo radio station. A complete description is inappropriate, so here an overview is offered. For further details please contact Technical Support for a copy of the user manual.

RB-OA3 On-Air Switcher - Three Studios

The unit connects three stereo audio pairs to the equipment room. These are switched to connect to one of the three 'Studios'. They are switched using latching relays, so can be used in either direction, and remain connected if power is lost. One pair is the stereo transmission path. The other 'peripheral' paths may be used for such purposes as telephone hybrid connections, or codecs for incoming contributions. A fourth stereo pair is also switched. This sends to the studio a feed of the 'last studio to offer' so that this may be faded to air and a seamless changeover between studios may be accomplished. One more stereo input is provided for a 'transmission mix' feed, intended to inject a service such as an automated jingle or advert play-out system directly into the transmission system without going through the studios. One of the 'studio' connections may be used for the connection of a sustaining service such as a PC based automation system, off-air tuner, incoming satellite feed or other programme circuit.

Internal logic provides for a studio to 'offer' control to the other studios, which can then be accepted by another studio; that studio then has control of the transmission and the delay system, if fitted. Where one of the 'studio' connections is used for a sustaining service, which may not be able to 'offer' control, a special key-press sequence is used to take control by another studio.

An RB-OA3 can be expanded to switch between up to five studios or up to six stereo pairs by connecting a multiple of units together via RJ45 serial connections. With the addition of a single unit, expansion in 'studio' mode allows for two additional studios to take control of the transmission path and additional equipment. If the expansion is made in 'bus' mode, then three additional stereo channels can be added. Four RB-OA3 units can be connected together to switch six stereo pairs between up to five studios. Each additional unit requires an RB-OA3C expansion unit cable kit.

The front panel of the 1U rack-mounting case has a power LED and status indicators for Dump, Delay, Offer, Studio 1, Studio 2, Studio 3. On the rear are D-sub connectors for audio and control. Two serial ports and a miniature switch bank provide control and configuration for expansion. Power is input by an IEC connector with adjacent fuse-holder.

Control panels are available for Sonifex S2 consoles, which may also be fitted to other equipment. The RB-OA3R remote switch panels are also suitable, see below. Alternatively control may be implemented using customer-provided circuitry using momentary push-buttons and indicators.

Included accessories: Handbook, AC power cordset with plug.
Optional accessories: The RB-RK3 (1U) rear-panel kit allows the device to be rack-mounted in reverse, with connectors outward. The RB-OA3R Remote switch panels may be used in each area where remote control is desired. RB-OA3C expansion cables may be used to add an extra RB-OA3R to an existing unit.

RB-OA3C Expansion Unit Cable Kit - For RB-OA3

If another RB-OA3 is added to an existing unit, three cables are needed to connect it. The kit contains 1x transmission output expansion cable, 1x LSO expansion cable and 1x RS232 expansion cable. All are 300mm long.

RB-OA3R Remote Switch Panel - For RB-OA3

Where there are no suitable panels for fitting custom switches for remotely controlling the RG-OA3, this standard control panel can be used. It is 1U rack mounting, for fitting in studio furniture or equipment racks.

The front panel has four LED-illuminated push buttons which are used to control the 'OFFER', 'ACCEPT', 'DELAY' and 'DUMP' functions. The rear panel has a single 15-pin D-sub connector to connect to the RB-OA3, which provides the power for the remote panel.

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SONIFEX RB-OA3 ON-AIR TRANSMISSION SWITCHER Analogue, 3 studio, stereo Stock code: 95-637
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SONIFEX RB-RK3 RACKMOUNT KIT Rear panel - reverse mount, for 480mm wide types Stock code: 95-639
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SONIFEX RB-OA3C CABLE KIT For RB-OA3 expansion unit Stock code: 95-626
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SONIFEX RB-OA3R REMOTE SWITCH PANEL For RB-OA3, 1U rackmount Stock code: 95-625
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