Mcbus Operation; Mcbus System Test - Cyrus 6 Service Manual

CYRUS 6 & 8 – MCBus Operation
MCBus
MCBus is a system which provides communication between the control systems of a number of
Cyrus products. The communication takes the form of a serial data stream which is sent from a
'master' product and received and repeated by 'slave' products. The data is thus passed from one
product to another around a loop. The master product should then receive the message back
which confirms that loop connections have been correctly made. The Cyrus 8 is a 'master'
product and sends commands following certain key sequences. Products such as CD players and
tuners are 'slaves' and only listen to MCBus for commands which may be appropriate.

MCBus system test

The MCBus system can be tested by substituting the amplifier into a known working Cyrus
system with a CD player or tuner. Note that MCBus must be connected as a closed loop. It is
also important to connect the audio signal cables between components to provide an adequate
ground return path for the MCBus signals. Switch on the power to the system and set all
components to Standby. Selecting an input on the amplifier will now activate both the Cyrus 8
and the selected device (tuner or CD as connected). When the Cyrus 8 is set to Standby, all other
components connected to the MCBus loop will also set to Standby.
7 Jan 2006