[time-nuts] Best Rubidium Frequency Standard

timenut at metachaos.net timenut at metachaos.net
Sat Mar 12 08:06:51 EST 2016


Joseph,

There are a few data points that lead to this conclusion...

   1. Look at the images on eBay for various PRS-10 and TSD-12 auctions. You
      will see that they all have the same customer part number 143-44101-xx
      where xx is 04, 08 or 10. Further, you will find a PRS-10 and a TSD-12
      with the exact same customer part number of 143-44101-08. This indicates
      that the TSD-12 is a "drop-in" replacement for the PRS-10 for that
      customer.

   2. In the timenut's archive, there is a user who has / had both. He
      reported that the TSD-12 self-reports as a PRS12, and additionally
      have the same firmware version number.

   3. The PRS-10 and TSD-12 are physically and electrically identical based on
      the various eBay pictures. There are two variations that I see. The
      first is that on apparently newer devices the back side has four
      mounting holes not present on the older devices. The second is that on
      some devices the Cannon connector is on the bottom rather that on the
      back end. All of the TSD versions (-11 and -12) appear to have the
      mounting holes. Like the PRS-10, some have the Cannon connector on the
      back end and some have it on the side.

   4. The same user reported that all of the PRS-10 devices he examined had
      the default locking mode of 1 and the TSD-12 devices had a default
      locking mode of 3. However, the LM command allows the locking mode to be
      set, and there is another command that will make that change to the
      power up state.

   5. Since the package is physically identical, the firmware is physically
      identical, if you look at the service manual, there are not a lot of
      things that could be changed or omitted. Almost everything is in
      software, including the 1 pps locking (which hijacks the trim pot to do
      its dirty work).

   6. The only option listed on the SRS site for new devices is an option that
      has a reduced aging rate (at an extra $495). There could be some other
      minor options like that, but effectively it appears as if the TSD-12 (or
      -11) is interchangable with the PRS-10 if the LM command is used to set
      the default locking mode.


Mike


>>       Or, perhaps not. The two working TSD12s that I see on eBay (apparently
>>       the same as the PRS-10 except the lock flag is set to 3 instead of 1 and
>>       which can be reset)

> Would you elaborate on this? I Googled for TSD12 and except for the
> auction listings, found nothing.

> Joe Gray
> WW5JG



-- 
Best regards,
 Timenut                            mailto:timenut at metachaos.net



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