This article is about the device used in satellite TV installation, for overcurrent protection devices see Resettable fuse

Resettable fuse

A polymeric positive temperature coefficient device is a passive electronic component used to protect against overcurrent faults in electronic circuits...

A multiswitch is a device used with a quattro LNB to distribute satellite TV signals to multiple (usually more than four) receivers from a single dish

Satellite dish

A satellite dish is a dish-shaped type of parabolic antenna designed to receive microwaves from communications satellites, which transmit data transmissions or broadcasts, such as satellite television.-Principle of operation:...

 and LNB

Low-noise block converter

A low-noise block downconverter is the receiving device of a parabolic satellite dish antenna of the type commonly used for satellite TV reception...

.

A typical K_u band universal LNB can be switched between four modes (two frequency ranges and two polarisations) selected by signals from the receiver (supply voltage for polarisation and presence or absence of a 22 kHz tone for frequency range). This means that each receiver needs a separate feed and twin-tuner receivers (such as Sky+

Sky+

Sky+, or Sky Plus, is a personal video recorder service for Sky in the UK. Launched in September 2001, it allows the user to record, pause and instantly rewind live TV. The system performs these functions using an internal hard drive inside the Sky+ set top box...

 and Freesat+

Freesat+

Freesat+ is a consumer brand created to raise consumer awareness and promote sales of Freesat-capable digital TV recorders, otherwise known as personal video recorders...

) need two separate feeds. For small numbers of receivers a multi-output LNB is used and all the feeds are taken straight from the LNB but there is a limit to the number of outputs that can reasonably be placed on a LNB.

So for larger installations a quattro LNB is used in conjunction with a multiswitch. The quattro LNB provides the signals for all four of the modes at the same time. The multiswitch then selects which of these signals to send to each receiver . For very large installations the signals from the LNB can be split and fed to more than one multiswitch. Typically a larger dish is used to make up for the extra losses in the longer cable runs and the multiswitches.

Some multiswitches can also mix in terrestrial TV and FM radio signals which can then be split out again by a special faceplate (known as a triplexer). Such Integrated Reception Systems

Integrated reception system

An integrated reception system provides broadcast signals from multiple sources to multiple outlets, via a single aerial cluster and signal booster-distributor...

 allows satellite, TV and radio service to be supplied down a single cable saving on installation costs.

Multiswitches are commonly installed on or in blocks of flats in the UK to allow all the residents to receive satellite TV without having to have a separate dish for every resident.

See also

• Crossbar Switch
  Crossbar switch
  In electronics, a crossbar switch is a switch connecting multiple inputs to multiple outputs in a matrix manner....
  
  - generic description of a switch connecting multiple inputs to multiple outputs in a matrix manner.