[time-nuts] Lucent KS-24361, HP/Symmetricom Z3809A, Z3810A, Z3811A, Z3812...

GandalfG8 at aol.com GandalfG8 at aol.com
Fri Oct 24 02:19:58 EDT 2014

Ah, hadn't spotted the latches.
I've used something similar in the past, might still have a couple around  
somewhere, but my first inclination would be to convert them to standard 
screw  types.
That's assuming they would fit of course, but Anthony's photos suggest they 
In a message dated 24/10/2014 06:26:26 GMT Daylight Time,  
tmiller11147 at verizon.net writes:

I am  surprised the schematics for these have not surfaced yet. Are they 
out  of support now?
I got a set and am awaiting on a power supply and some  connectors. Anyone 
have a source for the latches for the D  connectors?


----- Original Message ----- 
From:  "Anthony Roby" <aroby at antamy.com>
To: "Discussion of precise time and  frequency measurement" 
<time-nuts at febo.com>
Sent: Thursday,  October 23, 2014 10:39 PM
Subject: Re: [time-nuts] Lucent KS-24361,  HP/Symmetricom Z3809A, Z3810A, 
Z3811A, Z3812...

> My  curiosity got the better of me so I ordered these earlier this week 
> received them today.
> I've powered both up and quickly  measured the 10MHz output.  I don't yet 
> have a GPS antenna feed  that I can connect, so couldn't check that out. 
> And I need to look  into why both of the units have the Fault and StdBy 
> lights  illuminated.  I was surprised how compact they are and they 
> next to nothing.  And they are very nicely made.  I took  the tops off 
> and took some photos (see http://goo.gl/87e8GG),  but have not ventured 
> into unscrewing everything to get to the bottom  of the boards.  From the 
> top, I didn't immediately spot anything  extra on the board for the 10MHz 
> out.  All the extras appear to  be for the GPS, but the underside of the 
> boards may tell a different  story.
> Anthony
> -----Original  Message-----
> From: time-nuts [mailto:time-nuts-bounces at febo.com] On  Behalf Of Bob 
> Stewart
> Sent: Thursday, October 23, 2014 12:20  PM
> To: Discussion of precise time and frequency measurement
>  Subject: Re: [time-nuts] Lucent KS-24361, HP/Symmetricom Z3809A, Z3810A, 
> Z3811A, Z3812...
> My units came in today. What I got  appears to be new-in-box. It's 
> the only thing I'll ever get  with a blue Agilent sticker on the box. =) 
> has a yellow  Symmetricom notice inside the box.
> The circuit board appears to be the  same on both units, but that says 
> nothing about the firmware, of  course. The REF-1 has an Oncore receiver 
> labeled TM-AB - whichever  one that is, small parts to support it, and a 
> TNC connector for the  GPS receiver.
> The REF-0 is missing everything related to the  receiver, and has an SMA 
> for the 10MHz output in the space where the  REF-1 has the TNC along with 
> few extra small parts. This is a  shared space with both SMA and TNC 
> though they don't seem to  share the same electrical path. Since the SMA 
> and TNC share the same  physical space, even if the 10MHz is available 
> somewhere, you'd have  to do some surgery on the case before you could 
> bring it out.  Probably by adding a hole in the case for the GPS antenna 
> and using  the pad space for the SMA.
> It will be a day or two before I  have the bits to apply power and 
> an antenna. So, that's what  I know. I'd probably just break something if 
> tried to find and  bring out the 10MHz, so I'll have to leave that to 
> someone else. But,  the appropriate signals need to get between the 
> so I wonder  what's on the Interface pins? Maybe just arbitration, 1PPS, 
> and  sawtooth comms?
> In my case, I do need the 10MHz, so I'm just as happy  to have bought 
> units at this point. Maybe, down the road,  someone will come up with the 
> mods to convert a REF-1 into a REF-0,  and vice versa, unless the 
> prevents that.
>  Bob
>     From: GandalfG8--- via time-nuts  <time-nuts at febo.com>
> To: time-nuts at febo.com
> Sent:  Tuesday, October 21, 2014 5:59 AM
> Subject: Re: [time-nuts] Lucent  KS-24361, HP/Symmetricom Z3809A, Z3810A, 
> Z3811A,  Z3812...
> It seems from the auction revision table that this  seller has been 
> offering  these for some time, so perhaps  another "hidden" gem:-), but 
> it's perhaps also worth noting that if  this system functions on similar 
> principles to earlier RFTG kit then  the GPS conditioning is only applied 
> to the unit actually containing  the GPS module, with the other unit 
> intended as a standby should the  first one fail.
> In other words, unless the system redundancy  is really required most 
> would probably only need the GPS based  unit, or would at least be better 
> off buying two of those for the  same money that the "matched" pair would 
> cost.
> The  only advantage, as far as I'm aware anyway, of the non-GPS unit is 
>  that  it contains a 10MHz output.
> However, Skip Withrow published  modification details in January 2013 
> showing how straightforward it  was to add the the 10MHz output, to the 
> RFTGm-II-XO module, the PCB  location for the socket was already 
> so I would suspect it  wouldn't be too difficult on these either.
>  Regards
> Nigel
> In a  message dated 20/10/2014 05:53:29 GMT Daylight Time, 
>  stewart.cobb at gmail.com writes:
> Fellow  time-nuts,
> This (long) post is a review of the HP/Symmetricom  Z3810A (or Z3810AS) 
> GPSDO system built for Lucent circa 2000. I wrote  it because I looked 
> more information before I bought one, and  couldn't find much.
> It's relevant because (as of this writing), you  can buy a full system on 
> the usual auction site for about $150 plus  shipping. For those of you 
> lamenting the dearth of cheap  Thunderbolts, this looks like one of the 
> best deals going. The  description of these objects does not include 
> "GPSDO", so time-nuts  may have missed it. Search for one of the part 
> numbers in the subject  line and you should find it.
> So what is it? It's a dual GPSDO  built by HP as a reference (Redundant 
> Frequency and Time Generator,  or RFTG) for a Lucent cell-phone base 
> station, built to Lucent's spec  KS-24361. Internally, it's a close 
> of a later-model Z3805A.  Externally, it looks to be almost a drop-in 
> replacement for the  earlier RFTG system built to Lucent's spec KS-24019. 
> That was a  redundant system containing one rubidium (LPRO, in the one I 
> have)  and one OCXO in two almost-identical boxes. That spec went through 
>  several revisions with slightly different nameplates and presumably 
>  slightly different internals. You can generally find one or two examples 
> on the auction site (search for RFTG or KS-24019).
>  This system is similar, but the two boxes each contain a Milliren
>  (MTI) 260-0624-C 5.000MHz DOCXO, and neither contains a rubidium. The 
>  Milliren DOXCO is the same one used in the later models of the HP Z3805A 
> 58503A. It's a very high-performance DOCXO, in the same class as the  
> legendary HP 10811, and better than the one in most surplus  
> The 5 MHz output is multiplied up to 10 MHz in at least  one unit, and 15 
> MHz in both units. I don't have the ability to  measure phase noise on 
> these outputs, but I'd be interested to see  the results if someone could.
> Nomenclature: The Z3810AS (there  always seems to be an "S" at the
> end) is a system consisting of the  Z3811A (the unit containing a GPS 
> receiver), the Z3812A (the unit  with no GPS receiver), and the Z3809A (a 
> stupid little interconnect  cable). The GPS receiver inside the Z3811A is 
> Motorola device,  presumably some version of an OnCore.
> Where the Z3811A has a TNC GPS  antenna input, the Z3812A has an SMA 
> connector labeled "10MHz TP".  That is indeed a 10 MHz output. It comes 
> active as soon as power is  applied to the unit, and its frequency 
> the warmup curve of  the OCXO. The two units have identical PCBs (stuffed 
> slightly  differently), and I have no doubt that someone can figure out 
> to  add a 10 MHz output to the Z3811A as well.
> Operation: From the  outside, these units are broadly similar to earlier 
> units in the  Lucent RFTG series. The (extremely valuable) website run by 
> Didier,  KO4BB, has a lot of information on those earlier units, much of 
> which  still applies here. The purpose of these units was to provide a 
>  reliable source of frequency and timing information to the cell-site 
>  electronics. The 15 MHz outputs from both units were connected to a 
> combiner/splitter and directed to various parts of the transmitter.  The 
> units negotiate with each other so that only one 15 MHz output is  active 
> at a time. The outputs labeled "RS422/1PPS" contained a 4800  baud (?) 
> serial time code as well as the PPS signal, which were sent  to the 
> computer.
> Power is applied to the  connector labeled "+24VDC" and "P1", in exactly 
> the same way as the  earlier RFTG units. Apply +24V to pin 1 and the 
> side of the  power supply (GND or RTN) to pin 2. In these units, that 
> supply  goes directly to an isolated Lucent DC/DC converter brick labeled 
>  "IN: DC 18-36, 1.9A". Presumably you can run both units with a 4-amp 
>  supply.
> Once you have applied power, connect the Z3809A cable  between the jacks 
> labeled "INTERFACE J5" on each unit. The earlier  RFTG units used a 
> cable between two DE-9 connectors, and it  mattered which end of the 
> connected to which unit. The  interconnect for these units is a 
> high-density DE-15 connector (like  a VGA plug). The Z3809A cable is so 
> short that the two units need to  be stacked one above the other, or the 
> cable won't reach. It doesn't  seem to matter which end of the cable goes 
> to which unit. I don't  know whether it's a straight-through cable, or 
> whether you could use  a VGA cable as a substitute.
> When you apply power, all the  LEDs on the front panel will flash. The 
> GPS" light will continue  flashing until you connect a GPS antenna.
> Once it sees a satellite,  the light will stop flashing and remain on.
> The unit will conduct a  self-survey for several hours. Eventually, if 
> is well, the Z3812A  ("REF 0" on its front panel) will show one green 
> light and the  Z3811A ("REF 1") will show one yellow "STBY"
> light. This means that  the Z3812A is actually transmitting its 15MHz 
> output, and the other  one is silently waiting to take over if it fails.
> 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 
> the hood with a diagnostic program. The program is available on the  
> 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 
>  like this:
> 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.)
> With that  adapter, you can see the periodic timetag reports from the 
> The  RFTG program will interpret these timetags when it starts up in 
>  "normal mode". However, when I try to use any of the diagnostic features 
> built into the program, it crashes WINE. The timetag output was  required 
> for compatibility, but I suspect that HP didn't bother to  implement the 
> Lucent diagnostics.
> Instead, they added  a connector which is not on the previous RFTG 
> That connector  is labeled, logically enough, "J8-DIAGNOSTIC".
> It too is wired with  RS-422, so you need to use the same adapter cable 
> before. Once you  do, you'll find that this connector speaks the usual HP 
> SCPI command  set (Hooray!). I used the official SATSTAT program (again 
> under WINE  on 12.04 LTS), but I'm sure that other programs written for 
> this  command set will work as well. The default SATSTAT serial port 
>  settings of 9600-8-N-1 worked for me.
> After about 24 hours,  with a poorly-sited indoor GPS antenna, my system 
> has converged to  TFOM=3, FFOM=0 (the best possible numbers), and a 
> "predicted 24-hour  holdover uncertainty" of 5.2 microseconds, which is 
> too shabby.  It found the correct day and year without any assistance, so 
> if it  has a "GPS week number rollover" problem, it's still in the 
> I  don't currently have the ability to compare the 10 MHz output to 
>  anything else. Again, if someone else can, I'd be interested to see the  
> results.
> Additional Notes: The parts on the boards  all have date codes of 1998 or 
> 1999. The Motorola GPS receiver has a  firmware label that reads 
> "02/04/00". The SCPI error logs inside the  HP units were virgin when I 
> first got them. They had 84 and 94 power  cycles, respectively.
> Before the GPS receiver acquired time, the error  log timestamps read
> "2000-05-09 00:00:00", which I interpret as a  firmware release date.
> The PCB has an interesting feature.  Next to each soldered-in pin of the 
> Milliren OCXO is a single-pin  socket soldered into the board. I'm 
> this was used in  manufacturing, to temporarily install a Milliren and 
> confirm that the  system worked before permanently soldering it in. (At 
> production  prices, the Milliren would have cost far more than the rest 
> the  PCB.) You might be able to use this in reverse, if you have a set of 
>  Millirens to test from another source.
> The Z3809A interconnect  cable has three of the 15 pins on each end 
> a bit shorter than  the rest. Not so short that they won't eventually 
> contact, but  short enough to make contact later than the rest. Don't 
> why, but  it's clearly deliberate. A lot of hot-plug connectors are built 
> that  way, including USB connectors. I have no idea what the pinout of 
>  interconnect is.
> The redundant system slaves both DOCXOs to  the same GPS reference.
> Inside the GPS loop bandwidth, the two  oscillators will have almost the 
> same frequency and will differ only  by phase noise and short-term 
> stability. This is almost a perfect  setup for experimenting with certain 
> kinds of time-nut measurements,  assuming someone can figure out how to 
> 10MHz out of the Z3811A  unit. If you then command both units into 
> holdover, you could measure  longer-term stability as well.
> The units are described as "new  in factory sealed box". After an 
> archeological investigation of the  various strata of labels and tape on 
> the boxes, I would say that's  probably accurate. My set seems to have 
> shipped from the Agilent  factory in Korea to Symmetricom in Sunnyvale, 
> sometime in August,  2000, shortly after it was built, and remained 
> untouched until I  opened it. I'm guessing it was built and saved as part 
> of a spares  program for Lucent, and kept until Lucent decided they 
> need  spares any more.
> I have no connection with the current seller  of these units (or any 
> sellers, for that matter) except as a  satisfied customer. I think I'll 
> order another set as a spare, before  the feeding frenzy hits.
> Request for help: Both the SatStat  and RFTG programs run under WINE on 
> stock Ubuntu 12.04 LTS (32-bit)  without any tricks or special 
> configuration. Neither seems to run  under WINE on Ubuntu 14.04 LTS 
> (64-bit). I am a WINE novice. Any  hints from WINE experts would be 
> appreciated. Also, I've been able to  run TimeLab under WINE, but I can't 
> connect it to my USB-to-488  interface, so I can't take data. If anyone 
> tell me how to set  that up, I'd be extremely grateful.
> Cheers!
>  --Stu
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