There only two options: ExtraView, normally abbreviated as XV, whereby up to 3 decoders, can be combined under one subscription via a cable connected to the RF ports on the decoders, also used to distribute RF signals to multiple remote view locations, and; UniView, normally abbreviated as UV, whereby an SLNB or 24-1Z switch is used to relay the HB signal between up to 3 decoders. The choice of the method used depends on the decoder models and the types of switches and LNBs available, as well as what the RF distribution is required. UniView (UV) is only possible IF either an SLNB or a 24-1Z switch is available. The older LNBs (Quad, Quattro, Twin Universal) cannot relay HB signals. The original Explora Switches (ES's) are not capable of relaying the HB signals. ES 5-1 or ES 5-2. XV is possible with ALL decoder models capable of transmitting or receiving HB signals, but some models require the use of an external Diplexer. UV is only possible with decoders equipped with an internal Diplexer, or, with older models, an external Diplexer, IF one of the 3 SLNB models is available or a 24-1Z switch is available. The decision whether to use XV or UV depends on the location of the decoders and whether there is a requirement for distributing RF to multiple viewing points and whether remote control of the decoders is required from those multiple viewing points via tvLINKS. None of the older decoder models can be combined in a 3-decoder combination. The SD PVR, the HD PVR 4P, the HD PVR 4U, the HD PVR 2P and the older 11xx decoders cannot be used in a 3-decoder combination. The 3-decoder combination can be any of the Explora models, as well as the 4- and 5-series HD decoders. The Explora 1 and 2A both have RF IN and RF OUT ports. The 3A does not. The 4-series HD decoders have RF IN and RF OUT ports, the 5-series does not. The Explora 1 and 2A as well the 4-series HD decoders provide for HB transmission and reception via the RF ports. The Explora 2A has an internal diplexer which supports HB (Tx & Rx) via the Unicable port. The Explora 3A has an internal diplexer which supports HB (Tx & Rx) via the Unicable port. The 5-series HD decoders have internal diplexers which support HB (TX & Rx) via the Unicable port. tvLINK commands are relayed/received via the RF ports on the decoders with RF ports. The Explora 3A and the 5-series decoders relay/receive tvLINK commands via the Unicable port. BUT and here is the rub, the SLNBs and the 24-1Z do not relay tvLINK commands. (as per info received from MCA-David). Therefore, IF tvLINK control is desired, then an old style XV connection has to be used for HB and RF distribution.
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