If you have actively observed the development of satellite reception, then you will have noticed the extent to which switching criteria has changed. Control signals are needed to select the polarization levels, the frequency range, and satellite position, as well as to control steerable dishes, which are usually equipped with a separate polarizer. The interfacing is non standard and sometimes is even used for opposite purposes. In addition, transfer errors and voltage level drops occur, as well as electromagnetic interference caused by unshielded control cables.
In Europe, another conflict in the use of remote control signals came about with the introduction of the Hot Bird satellite system from EUTELSAT and the expansion of the ASTRA satellite system of SES. While ASTRA specified the 22 kHz tone to switch between the lower and the new upper frequency band within the LNB, EUTELSAT at first supported this to choose a satellite system with a multi-feed antenna. Some manufacturers started to develop receivers with additional company specific frequencies for yet another switching criterion, which led to more incompatibility and technical problems.
Phillips recognized this weakness and considered a new, flexible and reasonably priced system to control the total antenna periphery like LNBs and multiswitches, including polarizers and steerable antenna systems. EUTELSAT refined and finally specified the system under the name DiSEqC (Digital Satellite Equipment Control). DiSEqC is an open and unlicensed industrial standard available to anyone and is coordinated by EUTELSAT. DiSEqC™ is a trademark of EUTELSAT.