Ian Manley told me that he knew a retired BT engineer who worked specifically on work and maintenance which needed to be carried out in local exchanges of the type used to calculate a customer's bills using the old metering system (the forerunner to itemised billings)! Through this introduction it soon became apparent that if necessary, the police / powers that be could break a customer's uses of each and every unit of call time, so that the length and duration of individual calls could be identified, that had been made, from (in particular), a customer's telephone line! It was possible to do this I was told because in the banks of technology at these old fashioned exchanges, a unit of a customer's call time was registered via the Meter, by measuring periods of voltages recorded whenever a customer made a day time call, an cheap rate evening call, a week-end call, or an international calls. Apparently differently detected and recorded voltages became stockpiled in the memory of the meters.as a result a trained engineer could pinpoint or identify the duration of all calls which had been made at a particular time of day, evening or week-end etc...
Well. Of course was all very interesting to me, since here was an opportunity for the police to be able to prove, or to disprove that Neville Bamber had made that viral telephone call to Jeremy during the cheap rate period ( middle of the night on the 7 August 1985)? And, as it now turns out a second call from Neville Bamber, from the farmhouse to the police at Chelmsford at 3.26am..
We know that it was not possible to be able to find out the actual timing all these individual calls which could have been extracted at the local exchange if necessary could not give or provide a date when such a call, or a series of calls had actually been made, but this is where other factors might come into play - for example, the timing of police logs kept by Essex police...
Now, to somebody like myself, I could this all very intriguing...
Since, after discovering the existence of two police phone message logs, one timed at 3.26am, and another timed at 3.36am, I was interested in trying to discover the duration of the two logs in question, because I rather fancied the possibility of being able to discern one of these calls (in length) from the other, or and vice versa!