LTE reception and transmission zones - Basic Documentation - RMK770-1

Communication via the KNX bus

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Air conditioning controller
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Technical Documentation > Basic Documentation
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Some Synco devices allow for universal exchange of data on input and output terminals via KNX bus.

Principle of operation

  • Universal inputs, digital and analog outputs can be used as transmission objects (for transmission zones).

  • Universal inputs can be used as reception objects (in reception zones).

  • Data is exchanged as if the device terminals were connected by wire.

Number of reception/transmission zones

Max. 32 reception and transmission zones each are allowed per line.


Due to KNX bus-specific issues (e.g. transmission frequency), allowed or not allowed applications must be noted:

Examples for allowed applications

Use of universal transmission and reception zones is allowed and meaningful:

  • To control decentralized aggregates such as motors, pumps, etc.

  • For simple control functions that are not time-criticial.

  • Common processing or use of bus information.

Examples for not allowed applications

The following applications or input/output varaibles must not be implemented by means of universal transmission and reception zones:

  • Safety-related plants and equipment (e.g. fire shutdown, smoke extraction, frost protection).

  • If "simultaneous startup response of plants is active.

  • Applications where communications failure of transmission or receptions zones can cause damage.

  • Control paths that are time-criticial or more sophisticated (e.g. speed control via pressure, humidity).

  • Compulsory main control variables that must be available.

  • Acquisition and evaluation of pulses.


After power-up, a short time may pass until the bus signals are available. Fault plant behavior may result in the case of not allowed applications of the transmission and reception zone.


To activate the function, the desired transmission or reception zone must be set at a terminal in the device. The partner device must be set accordingly.


Transmission/reception operations are a 1:n-ratio, i.e. a transmission/reception zone may contain one "transmitter", but several "receivers". A value can be sent and received via the input terminal. Via the output terminal, a value (digital or 0…10V) can only be sent.

Example 1

RMS705B (device 1) contains the air quality value of an air quality sensor. This value is transmitted as transmission object via an analog output and further processed by a RMS705B (device 2).

Data exchange concept

The following transmission and reception zone is engineered for our example:

RMS705B, device 1 RMS705B, device 2 Value
Terminal Transmission zone Terminal Reception zone
N.Y1 1 N.X1 1 Air quality mean value

= Transmit
= Receive


Device 1

The following is configured in RMS705B, device 1:

Main menu > Commissioning > Communication > LTE transmission zones >

Operating line Range Factory setting
N.Y1 1

Device 2

The following is configured in RMS705B, device 2:

Main menu > Commissioning > Extra configuration > Input identifier >

Operating line Range Factory setting
N.X1 ppm

Main menu > Commissioning > Communication > LTE reception zones >

Operating line Range Factory setting
N.X1 1