[aprssig] NMEA ISSUE HELP
kg4wsv at gmail.com
Sat Feb 5 20:28:28 EST 2011
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).
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