When batteries are running out of power, the MCP will start flashing and show "Battery" in the display.
The "No communication" comes when the Beomaster doesn't reply to commands sent from the MCP.
Either the MCP doesn't send or the Beomaster doesn't receive or the Beomaster doesn't send or the MCP doesn't receive.
Something blocking the way between the two or the Beomaster is in a wrong option setting or some technical defect.

Martin

thank you

I am still getting the error 'No Contact' on my MCP5500 Master Control Panel. The fault seems to be intermittent. In normal use I have no problems with the MCP5500 communicating with my Beomaster5500 or Beogram6000. Is something else interferring with the signal perhaps e.g bluetooth phone device or is this not likely. I am just trying to rule things out/in.

Any advice is greatly appreciated.

This is a clever design,with consumption at virtually zero when in stand-by,so with daily,eg function select and volume commands,the batteries usually last well over a year in my experience.Use good quality batteries though.Duracell,Energiser or even Sainsbury's own brand,which are allegedly rebadged Energiser?

Avoid those "bargain basement"market stall  job's,they are cheap for a reason!

As Martin(Dillen) states,there is a two way communication between the Beomaster and MCP.Use your 'phone camera to see if the MCP is transmitting,and again to see if the Beomaster is acknowledging the command .

Do you have say, a Beolink 1000 to try,to see if the system functions with one way commands?

The most common cause of this problem is a failed or noisy infra red receiver diode in the Beomaster,but the problem could also be due the same failing in the MCP.

Do some more detective work,to try and narrow down the possibilities,and come back to us?

Nick