It's in the mail archives.  Google for something like >time-nuts RS422 pinout<

If you are interested in timing, you want the PPS signal too.  (It won't be
great over USB, but it might be fun to play with.  You can get your own
hanging bridges.)

--
These are my opinions.  I hate spam.

This is your link:
https://www.febo.com/pipermail/time-nuts/2014-October/087674.html
anyway, the J8 connector pinout:

KS-24361 J8 - Diagnostic serial port with SCPI 9600,N,8,1
RXD+  4
RXD-  8
TXD+  5
TXD-  9
GND  3, 7

J6 RS422/PPS
RXD+  4
RXD-  8 no information on this RX line
TXD+  5
TXD-  9    one string each second (no SCPI) 9600,N,8,1
pins 1 (+) and 6 (-) are the differential PPS pulse 400us wide

On Thu, Sep 22, 2016 at 8:07 AM, Hal Murray hmurray@megapathdsl.net wrote:

Be careful of the pps output from the dual lucent boxes.  Tried to use it to sync SL and found that it is a weird non-standard pulse and would not work even with a pulse stretcher as it looked too narrow.  I use the pps output from a Jackson unit and it syncs SL fine.

73,

Bill, WA2DVU
Cape May

-----Original Message-----
From: time-nuts [mailto:time-nuts-bounces@febo.com] On Behalf Of Hal Murray
Sent: Thursday, September 22, 2016 2:07 AM
To: Discussion of precise time and frequency measurement
Cc: hmurray@megapathdsl.net
Subject: Re: [time-nuts] Lucent RFTFm-II-XO

It's in the mail archives.  Google for something like >time-nuts RS422 pinout<

If you are interested in timing, you want the PPS signal too.  (It won't be great over USB, but it might be fun to play with.  You can get your own hanging bridges.)

--
These are my opinions.  I hate spam.

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Hi

I have had no problem using the PPS out of any of the Lucent boxes. They trigger counters
fine and a one shot stretches them to any length you might need.

Bob

Hi Bob,

If you could,  would you see if you can take the pps out of your lucent box and use it to sync the pc sound card clock via continuous calibration for  using SL for fx measurements.  Maybe by lucent box pps output is bad.

15625 from 3586 goes in one channel and pps goes into the other channel of the sound card and SL does its magic.

73,

Bill, WA2DVU
Cape May

-----Original Message-----
From: time-nuts [mailto:time-nuts-bounces@febo.com] On Behalf Of Bob Camp
Sent: Thursday, September 22, 2016 12:55 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Lucent RFTFm-II-XO

Hi

I have had no problem using the PPS out of any of the Lucent boxes. They trigger counters fine and a one shot stretches them to any length you might need.

Bob

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and follow the instructions there.

Hi

If the PPS is going to run into a run of the mil sound card, the pulse width likely will need to be > (1/20,000) s. That will require a one shot to do. The Lucent PPS is a bit narrower than that, as is the output of a lot of GPSDO’s.

Bob

Bill wrote:

The PPS directly out of most GPSDOs is too fast for sound cards.  But
once you stretch it, there is another problem.  Assuming 5v logic, and
knowing that the sound card is AC coupled, the leading edge of the
(assumed positive-going) pulse will produce a 5v spike that decays over
a time period that depends on the post-capacitor DC resistance inside
the sound card.  It might decay fully (back to 0v) during the pulse, or
less than that.

The falling edge of the pulse will generate a negative-going spike with
a peak negative voltage of [decayed voltage after leading edge minus
5v].  This could be anywhere from just slightly negative to the full
logic supply (if the post-capacitor voltage decays fully before the
falling edge occurs).  The same would be true for 3.3v logic,
substituting "3.3" for "5" above.

These peak voltages are way outside the input range of most sound cards,
so the positive spike is almost certainly going to overload the ADC,
with unpredictable (and, very likely, unfortunate) results.

At the very least, you will need some sort of sound-card oscilloscope
program so you can see what the sound card is actually capturing.  Then
you can start shaping your trigger pulses (with voltage clamping and
possibly LP filtering) to give predictable and stable results.

Best regards,

Charles

One additional point:  Many ordinary PC sound cards do not have proper
input filtering, so anything as fast as a PPS pulse will cause severe
aliasing, even after it has been voltage-clamped to a level that will
not overload the ADC.  (Thus my mention of LP filtering under pulse
conditioning.)

The sound cards that do have adequate input filtering generally use
rapid-cutoff filter alignments, which can ring like crazy -- very much
what you do not want when you are trying to use a pulse for timing.

So:  Best to slow the pulse rise- and fall-times down so you are not
banging on the input filter (if present), or causing aliasing.

Best regards,

Charles

You may even be lucky enough to see brief periods of phase reversal on some
of the amplifiers on the input chain, adding more edges.

On Thu, Sep 22, 2016 at 3:47 PM, Charles Steinmetz csteinmetz@yandex.com
wrote:

Hi Charles,

Thanks for info - makes sense.  With SL Lucent pulse did not work - Jackson unit did with no mods.  Guess I was lucky!

73,

Bill, WA2DVU

-----Original Message-----
From: time-nuts [mailto:time-nuts-bounces@febo.com] On Behalf Of Charles Steinmetz
Sent: Thursday, September 22, 2016 3:48 PM
To: time-nuts@febo.com
Subject: Re: [time-nuts] Lucent RFTFm-II-XO

Bill wrote:

The PPS directly out of most GPSDOs is too fast for sound cards.  But once you stretch it, there is another problem.  Assuming 5v logic, and knowing that the sound card is AC coupled, the leading edge of the (assumed positive-going) pulse will produce a 5v spike that decays over a time period that depends on the post-capacitor DC resistance inside the sound card.  It might decay fully (back to 0v) during the pulse, or less than that.

The falling edge of the pulse will generate a negative-going spike with a peak negative voltage of [decayed voltage after leading edge minus 5v].  This could be anywhere from just slightly negative to the full logic supply (if the post-capacitor voltage decays fully before the falling edge occurs).  The same would be true for 3.3v logic, substituting "3.3" for "5" above.

These peak voltages are way outside the input range of most sound cards, so the positive spike is almost certainly going to overload the ADC, with unpredictable (and, very likely, unfortunate) results.

At the very least, you will need some sort of sound-card oscilloscope program so you can see what the sound card is actually capturing.  Then you can start shaping your trigger pulses (with voltage clamping and possibly LP filtering) to give predictable and stable results.

Best regards,

Charles

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