[time-nuts] The Trimble NTPX26AB-06 / Z3801A

[Roy Phillips]

Hal
Thanks for your kind help. You are certainly right about the PECL level 
signals from the I/O connector, but this is where the similarity stops, as 
the Trimble unit is to all intents a substitute for the Z3801A, but 
internally its quite different. In the interests of costs, it would seem 
that there is no RS-232 facility. There is a sub PCB that carries the LED's 
at the front of the unit via a connector, and there is a location on this 
PCB for a for a 9-pin D connector!.  If this had been used it would have 
made a serial port available at the front panel. More interesting is that 
there are tracks feeding what would have been pins 2,3 and 5 !
Perhaps there was an intention in the original specification to provide a 
"service" serial port to the front of the unit - but would this have 
provided RS-422 and not RS-232 signals ? Unfortunately, Trimble will not 
offer any information on this unit, as it was made for Nortel, and I have so 
far not been able to find any alternative information except for a brief 
reference in the Z3801A article.

Roy


----- Original Message ----- 
From: "Hal Murray" <hmurray at megapathdsl.net>
To: "Discussion of precise time and frequency measurement" 
<time-nuts at febo.com>
Sent: Saturday, November 22, 2008 6:27 AM
Subject: Re: [time-nuts] The Trimble NTPX26AB-06 / Z3801A


>
>> On the Z3801a, if you want to use the 1-PPS or 10MHz signals that are
>> on the DB-25 you will need to convert the PECL outputs.
>
> If you are willing to lift a pin and cut a trace, you can get the PPS on
> RS-232 without any external level conversion.  The fine print is in here:
>  http://support.ntp.org/bin/view/Support/Z3801AReceiverModifications
>
> I used a non-standard pin on the DB-25 in order to avoid cutting a trace, 
> but
> I was building my own 25 to 9 pin adapter so that was easy fix.
>
>
>
> -- 
> These are my opinions, not necessarily my employer's.  I hate spam.
>
>
>
>
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