[time-nuts] RS-232 Pin Outs for the Acron Zeit WWVB LCD Clock
hmurray at megapathdsl.net
Sun Jul 23 09:26:03 EDT 2017
TimeNuts at philipjackson.com said:
> I'm wondering if something like this $10 item
That setup has a separate pin (hole?) for power. It's setup to expect Gnd,
Tx, Rx, and Pwr from the TTL side.
A previous message said the module designed for the job had a diode. I'd
expect that is using power from one of the modem control signals.
You could probably add a diode to make it work.
> I don't know if I've seen an inverting one and that would seem a more costly
> approach than handling the inversion on the clock board.
Almost all TTL to RS-232 level shifter chips include an inverter. It's just
historical. The first chips (MC1488, MC1489) did it that way and everybody
who makes a new chip includes the inverter too so they can cleanly replace
These are my opinions. I hate spam.
More information about the time-nuts