[Pellseinydd]

The 'X' appeared from memory around the time of approaching STD introduction. On those days, when a caller on a 'call office line' (the GPO term for a line with a con collecting box on it) dialled '0' for the operator, the call arrived on the manual board on a line with a red opal (light) so the operator knew it was from a coinbox. Reverse charged calls were not allowed to a call office number. Sometimes it was possible to dial the code to another exchange followed by a '0' in which case the call arrived as a all from an 'ordinary' line and operator treated it as such until when she asked for the number and was told it was ......X when they then realised it was a 'fiddled' call.

But once STD was introduced, POA (Pay on Answer) payphones were introduced. When '100' was dialled to reach the operator, rapid 'pips' were put on the line when they answered, by the 'Coin & Fee Checking' relay sets in the exchange. The operator then knew it was from a coinbox.

Ian
CNet 0352 2345
MR ETD 053-6278