DiSEqC pour techniciens
[3.0] Introduction
With DiSEqC, a system has been created with more capacity than required for today’s uses. Although all currently conceivable applications have been considered and specified, additional functions can be implemented at any time due to the flexibility of the system. DiSEqC defines a uniform and brand neutral standard, which is set to eventually replace the available analog and sometimes company specific control systems. In order to ensure a smooth transition, DiSEqC may also be installed in addition to available analog switching criteria.
During the development of DiSEqC much attention was paid to a cost-effective implementation. Most satellite receivers can give DiSEqC commands with only small software changes in the existing microprocessor. In comparison, more expenditure is necessary in the periphery components. Here, a small mask-programmed microcontroller (83C750) must be incorporated, which nevertheless, can replace a part of the previous detection logic.
DiSEqC is designed for two-way communications, i.e. a multiswitch can confirm the execution of a switch command (automatic error search, if required) or the receiver can "ask" the LNB for the available local oscillator frequencies (automatic receiver installation). Problems with the threshold levels due to voltage drops in the downlead cables are eliminated since the signaling is independent of voltage levels. In addition, the receivers‘ power supplies will become more economical due to the constant remote voltage in future. Furthermore, considerable energy savings are made possible by reducing the voltage.
DiSEqC is a "single master / multi slave "system", which means the signal traces are structured in a way that multiple DiSEqC masters (receivers) never access the same slave. Therefore in a multiswitch, each active output has its own slave assigned. On the other hand, a master can control several slaves (LNBs, multiswitches etc.). This concept precisely complies with the distribution structure of SAT-IF. All DiSEqC activities go out with the master, which means that a slave can only send data when prompted by the master.
During the development of DiSEqC much attention was paid to a cost-effective implementation. Most satellite receivers can give DiSEqC commands with only small software changes in the existing microprocessor. In comparison, more expenditure is necessary in the periphery components. Here, a small mask-programmed microcontroller (83C750) must be incorporated, which nevertheless, can replace a part of the previous detection logic.
DiSEqC is designed for two-way communications, i.e. a multiswitch can confirm the execution of a switch command (automatic error search, if required) or the receiver can "ask" the LNB for the available local oscillator frequencies (automatic receiver installation). Problems with the threshold levels due to voltage drops in the downlead cables are eliminated since the signaling is independent of voltage levels. In addition, the receivers‘ power supplies will become more economical due to the constant remote voltage in future. Furthermore, considerable energy savings are made possible by reducing the voltage.
DiSEqC is a "single master / multi slave "system", which means the signal traces are structured in a way that multiple DiSEqC masters (receivers) never access the same slave. Therefore in a multiswitch, each active output has its own slave assigned. On the other hand, a master can control several slaves (LNBs, multiswitches etc.). This concept precisely complies with the distribution structure of SAT-IF. All DiSEqC activities go out with the master, which means that a slave can only send data when prompted by the master.
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