[time-nuts] The other Trimble - NTPX26AB-06

[Roy Phillips]

I have just received a Trimble NTPX26AB-06, to add to the TBolt which performs perfectly. I am aware that some exchanges have taken place in the past with reference to this unit which it would seem was a Trimble design to offer a less expensive alternative to the HP- Z3801A.
The obvious difference with the TBolt's facilities would seem to be the single BNC 10 MHz output, and the I/O (25 way "D" connector) which provides an RS-422 serial interface with TBoltMon and your  PC.
I do not have an RS-422 adaptor or PC card at present, and I am wondering if it is necessary to obtain one in light of the article investigating the HP-Z3801A. This makes it clear that the Z3801A had the facility to be simply modified by strapping, to change to RS-232 interface. I have examined my NTPX26AB-06, and find that on the narrow secondary PCB that carries the six status LED's on the front panel, there is a location (unpopulated), for a 9 pin PCB mount "D" connector, which if it was fitted, would protrude out of the front of the unit. More to the point, there are tracks to pins 2,3 and 5 which are carried back to the main PCB via the interconnection cable, which would appear to be carrying  data to this location. I have not had time to investigate this further, but it would seem that Trimble had made this facility available as part of the specification, but it was unused ?

Question, if it is a normal RS-232 (Trimble) interface, is it likely that it would be usable without modification ? -  - is it possible that both interfaces are accessible at the same time  - - or would one have to "switch" the other output off ?   Further, I find that the I/O ( 25 way "D" ), offers the same additional 10 MHz and 1 pps signals as the Z3801A, although at non-standard levels. If anybody has investigated this unit and has been successful in modifying this facility, I would be pleased to have the information. I would rather have this unit interfaced with my existing RS-232 interface, than seek additional RS-422 equipment.

I apologize if I am covering "old ground", but I would appreciate any information on this item.

Thank you

Roy Phillips