I've deciphered most of my father's RAF service record with the help of this excellent site. Just a few entries are still a mystery: EX-REM: WOPG - is REM an initial exam for Wireless Operator (Ground)? It came shortly after call up from the Reserve IMTS - this comes after training at 2 Signals School RAF Yatesbury and joining 512(G)MSU, a Mobile Signals Unit which was attached to 53 Mobile Field Hospital (as I've gleaned from this site). The date for IMTS is two weeks before rejoining the MSU, and 3 months before moving to the continent on 18/6/44. Is TS a training school? 55145(CB)MSU - he was transferred to this Mobile Signals Unit on 12/11/45. Any ideas what type of MSU 'CB' was? I'd appreciate any suggestion for these. My father moved with the MSUs through France, Belgium, Germany and Holland.