15 Feb
2008
15 Feb
'08
7:48 a.m.
Why do you say 'very hard'? I'm not sure
when the relay was invented, but I
suspect it was way before 1901, given that the concept of an electromagnet was
so much earlier.
By 1901 relays were common items. Western Union did much of the
perfection in the mid/late 1800s.
I seem to recall that this was about the biggest
problem in getting Colossus
to work in the 1940s; the technology for doing the optical detection of the
tape data just wasn't really 'there' yet, not at any speed. I think the
maximum they managed to get was around 8KHz, but it wasn't particularly
reliable (I think 5KHz was the norm, and it took an awful lot of initial
effort to get that working properly).
I am not sure what the photocells of 1920 were up to, but by 1940 they
were not half bad, with so many being used for FAX service. 8 KHz may
be about right for off the shelf tubes.
--
Will