## Tuesday, 9 October 2012

### Telephone area codes explained!

My brother-in-law, Ron (who, as I have mentioned before, is an amazing source of information about many things) has enlightened me about telephone area codes (see my previous blog).

He writes:
 As an ex-telecom engineer maybe I can answer your question.  Before the introduction of MF (multi frequency) signalling in the telephone network, your telephone told the exchange what number you had dialled by using pulses of electricity. '1' gave 1 pulse, '2' = 2 pulses etc. but 0 (zero) pulses could obviously not be sent. You will notice that '0' comes after '9' (on the telephone keypad), hence '0' is in fact ten!  The pulses were used to step electro-mechanical selectors. 1 would step up to level one plane, hence 0 would step to level ten plane. So zero within the telecom network did not mean nothing.  With reference to the Norwich dialling code, the zero was/is the access code to the STD (Subscriber Trunk Dialling) level; the 1 was placed after the zero to increase vastly the number of individual numbers available. The six (look on your telephone key pad) represented N and the zero after the 6 represented O (oh). So on the STD network the 603 in 01603 signals NO(rwich)3, which would route to Norwich. Similarly, 01539 after gaining access to the STD network (via the 01)would signal 539, which is KE(ndal)9; likewise, 01524 = 01 and then LA(ncaster)4.  Originally 01 was London (because they always think they are number one!) Then the 2 in 02 numbers represented B(irmingham), 3 = E(dinburgh), 4 = G(lasgow), 5 = L(iverpool) and 6 = M(anchester). Look on your telephone key pad and you will see these letter/number combinations! All clever stuff! Ron concludes: I bet you're sorry you asked, aren't you? No, I'm not! This is fascinating. Thank you. So, the zero definitely did not mean nothing originally. Nor did it mean 'nothing' as in 'send no pulses'; it originally meant ten (as in 'send ten pulses'). But that explains the historical source of the zero and what it once meant. But, nowadays, it seems to me that the zero at the start of every telephone number is superfluous, Because every single code starts with zero, it does not distinguish one code from another in any way. So, perhaps it does now mean nothing? Or perhaps it means, 'I used to be important, so I'm sticking around'. Or maybe it means that one day we might run out of codes and have to introduce codes that begin with something else (presumably 1?). What the zero definitely does not seem to mean in a telephone code like 01539 is 'nothing' in the sense of an 'absence of something'. In a counting number like 4208, the zero here represents 'an absence of tens'. This is what I mean by saying it represents 'nothing'.  So, in summary, if the zero at the start of a telephone area code does represent something then that something is not 'nothing'! And I shall continue to say that my telephone code is zero, one, six, zero, three!