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silverfox0786

05-11-10, 18:22

DiSEqC
DiSEqC (Digital Satellite Equipment Control), pronounced "Die-Sec", is a special communication protocol for use between a satellite receiver and a device such as a multi-dish switch or a small[1] dish antenna rotor. DiSEqC was developed by European satellite provider Eutelsat, which now acts as the standards agency for the protocol.

DiSEqC relies only upon a coaxial cable to transmit both bidirectional data/signals and power. DiSEqC is commonly used to control switches and motors, and is more flexible than 13/18 volt and 22 kHz tone or ToneBurst/MiniDiSEqC techniques. DiSEqC is also compatible with the actuators used to rotate large C band dishes if used with a DiSEqC positioner. Despite its name, it has been used on fully analogue or only partially digital-capable (Astra Digital Radio) satellite receivers.

A number of variations of DiSEqC exist:

DiSEqC 1.0, which allows switching between up to 4 satellite sources
DiSEqC 1.1, which allows switching between up to 16 sources
DiSEqC 1.2, which allows switching between up to 16 sources, and control of a single axis satellite motor
DiSEqC 2.0, which adds bi-directional communications to DiSEqC 1.0
DiSEqC 2.1, which adds bi-directional communications to DiSEqC 1.1
DiSEqC 2.2, which adds bi-directional communications to DiSEqC 1.2
All four variations were standardized by February 1998, prior to general use of digital satellite television. The later versions are backwards compatible with the lower revisions, but the lower revisions are, as might be expected, not forwards compatible with the higher revision numbers. 1.x and 2.x versions are both backwards and forwards compatible. This table shows what works and what does not:

1.0 switch 1.1 switch 1.2 motor 2.0 switch 2.1 switch 2.2 motor
1.0 receiver yes no no yes no no
1.1 receiver yes yes no yes yes no
1.2 receiver yes yes yes yes yes yes
2.0 receiver yes no no yes no no
2.1 receiver yes yes no yes yes no
2.2 receiver yes yes yes yes yes yes

Do note that a 1.x receiver will not be able to receive communication from a switch or motor. Usually this is not important, as the switch or motor can be controlled by the receiver without problems.

Eutelsat apparently developed the system to allow satellite users in Continental Europe to switch between the more popular SES Astra satellites at 19.2° east and Eutelsat's own Hot Bird system at 13° east. As a result, the vast majority of European satellite receivers support DiSEqC 1.0 or higher, with the notable exception of all set top boxes manufactured under the Sky Digibox name. All supporting receivers have received certification to carry a logo specifying which variation of DiSEqC they support.

Also often found are the terms DiSEqC 1.3 and 2.3 used by manufacturers and retailers to refer to the use of DiSEqC with other protocols. For example, 1.3 usually refers to a receiver which uses USALS in conjunction with the DiSEqC 1.2 protocol. Such terminology has not been authorised by Eutelsat.

DiSEqC uses a pulsed (tone-burst) 22kHz sine-wave at 0.5v peak to peak.

USALS
Universal Satellites Automatic Location System (USALS), also known (unofficially) as DiSEqC 1.3, Go X or Go to XX is a satellite dish motor protocol that automatically creates a list of available satellite positions in a motorised satellite dish setup. It is used in conjunction with the DiSEqC 1.2 protocol. It was developed by STAB, an Italian motor manufacturer, who still make the majority of USALS compatible motors.

Software on the satellite receiver (or external positioner) calculates the position of all available satellites from an initial location (input by the user), which is the latitude and longitude relative to Earth. Calculated positions can differ ±0.1 degrees from the offset. This is adjusted automatically and does not require previous technical knowledge.

Compared to DiSEqC 1.2, it is not necessary to manually search and store every known satellite position. Pointing to a known satellite position (for example 19.2ºE) is enough; this position will act as the central point, and the USALS system will then calculate visible satellites position within the offset.

Receivers are aligned to the satellite most southern to their position in the northern hemisphere, or the northernmost in the southern hemisphere.

As it is not an open standard, for a receiver to carry the USALS logo it must undergo a certification test by STAB's laboratories. If successful the manufacturer can include a USALS settings entry in its own menu, as well as place the logo on the front of their unit. However, a large number of manufacturers of both receivers and motors provide compatible modes which have not received certification, leading to use of unofficial terms

If your starting a new setup the USALS [hh390] motor and its ok with the vu