Originally Posted by winston_1
... was a universal 2 pin like UK shaver sockets and would accept UK 2 pin 5A plugs, 2 pin CEE 7/16, and US 2pin (but not the ones with one wider pin). Occasionally a US 3 pin socket was used and more recently schuko. ...

The standard socket looks like this:
[Linked Image from pewsth.panasonic.co.th]
The TIS 166-2549 plug is created by combining CEE7's "4.8mm" & nema 5-15's "ground"