CIR

Let's be honest, if you ask a railway worker in China what is CIR. They'll probably tell you it is 机车综合无线通信设备.

But that's not the end, the interesting part is, even they call that device CIR every day, they can still not be able to tell you the full name of CIR.

At the day I was writing this, I can not get the answer from Baidu.com

But I guess, CIR means Car Integrated Radio or Cab Integrated Radio communication equipment.