8 Oct
2001
8 Oct
'01
4:14 p.m.
--- Dave McGuire <mcguire(a)neurotica.com> wrote:
On October 9, Iggy Drougge wrote:
> But if I have a toasted line driver, wouldn't that strike both inbound
> and outbound data?
Nope... there's line drivers and line receivers.
Nope...many RS232 interfaces are built with 1488
driver and 1489
receiver chips. Nowadays the Maxim MAX232 (and family) chips are
popular for that sort of thing since they only require +5V...
Depending on the nature of the circuit - Maxim chips are somewhat
expensive. Older ones use external caps and those are comparitively
expensive, too. If you _don't_ have a ready supply of +/-12V, though,
a Maxim chip might be cheaper.
but I'll bet the VT420 uses 1488/1489 chips.
Since it's a modern DEC terminal, I'll bet it uses 9636/9637 chips. Those
came in with the VT220.
-ethan
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