[time-nuts] Mounting GPS Antenna on Steel Roof

[Matthew Smith]

Quoth Hal Murray at 2008-03-06 20:07...
>> I will be doing (4) as soon as I've found the time to make up a TTL to
>> RS232 board.
> 
> I suggest trying it without anything fancy.
> 
> All the GPS toys I've tried work fine without any conversion gear.
> 
> The normal TTL to RS-232 chips include an inverter.  That will break things 
> unless you add another inverter.  (or your gear expects an inverter)
> 
> The usual switching point for RS232 receiver chips is 1.4 volts.  That's the 
> switching point for TTL inputs, 2 diode drops above ground.  That works fine 
> for 3V CMOS drivers.
> 
> 

So my Trimble ACE II and Moto Oncore modules will tolerate RS232 levels 
without conversion?  Are we absolutely sure on this - I don't want to 
fry anything!

Cheers

M

-- 
Matthew Smith
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