[time-nuts] Lucent KS-24361, HP/Symmetricom Z3809A, Z3810A, Z3811A, Z3812A GPSDO system

Götz Romahn goetz at g-romahn.de
Thu Oct 30 14:24:21 EDT 2014

I also tried Steward Cobbs RS422 - Rs232 hack but with no joy in the 
beginning. First I had used the standard RS232 com1 port of my computer 
with no success. Later I tried my Prolific USB-to Serial adapter and 
things got better. After some measurments and looking at the pinout of 
the RS422/1PPS connector I've found somewhere on the Net, I made some 
additions to Stewards hack at the RS422 male plug:
connect pin3 (Ground) to pin4 (Rx+) and add an 150 resistor from pin 3 
to pin 5 (Tx+). This works reliable to the the Prolific but not reliable 
with the standard com1 port. The reason seems to be that the Tx- (pin 9) 
voltage swing re Ground is only abt. 3.5 V. This could explain the mixed 
success of other members.
hope this helps Götz

btw: will the RFTG-REF1 unit I have work standalone? I still have the 
STBY-led blinking after more than 24 hours and 3 to 8 satellites in 
view, all other leds off.

Am 30.10.2014 01:11, :
> HI
> There are a few possible variations:
> 1) Different power supply voltages
> 2) Cheating RS-232 versus a proper RS-422 converter
> 3) The “right” interface cable (what ever it’s pinout is) versus a VGA cable ( or no cable at all…)
> 4)  The HP interface versus the Lucent one
> 5) Windows 3.11 versus Windows 10 beta (or maybe something in-between).
> I’m only observing that some have had more luck with these than others. Since they are all NOS, they should all work. That suggests one or another hookup issue. I don’t think there is any need for ultra long detail lists. Stu took care a lot of that. I don’t have one, so at this point I’m just an observer on the sidelines.
> Bob
>> Most time-nuts want to see more than a pretty green light.  The old
>> RFTG series allowed you to hook up a PC to the "RS422/PPS" port and
>> peek under the hood with a diagnostic program.  The program is
>> available on the KO4BB website.  It is written for an old version of
>> Windows, and I had no luck getting it to run under Windows 7.  It does
>> run under WINE (the Windows emulator for Linux) on Ubuntu 12.04 LTS.
>> To use it, you need to make an adapter cable to connect the oddball
>> RS-422 pinout to a conventional PC RS-232 pinout.  The adapter cable
>> looks like this:
>> RFTG          PC
>> DE-9P         DE-9S
>> 7 <----------> 5
>> 8 <----------> 3
>> 9 <----------> 2
>> (According to the official specs, this is cheating, because you're
>> connecting the negative side of the differential RS-422 signals to the
>> RS-232, and ignoring the positive side of the differential signals.
>> However, it's a standard hack, and it's worked every time I've tried
>> it.)

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