[aprssig] NMEA ISSUE HELP

[Jason KG4WSV]

On Sat, Feb 5, 2011 at 6:54 PM, Andrew Rich <vk4tec at tech-software.net> wrote:
> Given that the GPS is TTL type logic,

No, it is not TTL logic, it's TTL voltages.  TTL signals are inverted
compared to RS232.  A logic high is 5V TTL but -12V RS232.

> can u suggest a TTL style chip apart
> from optos, that might be able to provide say 8 streams of "repeated" NMEA
> TTL data ?

I used a MAX237 and managed to pass 3 extra TX-only copies of the
rs232 data with a single IC (plus a few caps).

-Jason
kg4wsv