[time-nuts] Specifications of the older PicoSync GPS Engine communication protocol on the RS232 port?

[Hui Zhang]

Hello Juhua:


    I also have a similar GPSDO, it troubled me long times, beacuse I made a mistake of its model, I thought it's PICOSYNC II. So I use FEI's PicoSyncView program trying to connect it, but got no any response.  I think maybe FEI have a old version PicoSyncView program for this GPSDO, you may try to write a email to their tech-support:  techsupport at fei-zyfer.com. 
    If you have any progress, please let's me know. Thanks!




Hui






At 2013-07-19 18:13:41,"Juha Honkanen" <juha.honkanen at swipnet.se> wrote:
>Hi all
>
>I have a couple of the older PicoSync GPS Engines: http://www.trinstruments.cz/data/files/picosync-gps-engine-604.pdf
>
>They are working fine and producing good stable freq ref for my instruments. Please note that these are the first version and not the newer one PicoSync II.
>
>Is there any one here on the time-nuts list that has been able to reverse engineer the binary protocol that the PicoSync seems to be using on the RS232 port?
>
>It seems to be some proprietary protocol by FEI Inc (Frequency Electronics Inc) that I have not seen before.
>
>I see that the internal GPS receiver being used by PicoSync is a standard Trimble Resolution T (http://www.trimble.com/timing/resolution-t.aspx ) and when I connect to the GPS card directly I am able to communicate with the card via Trimble software and the TSIP protocol using 9600-O-8-1 comm parameters. I used the pretty good Trimble GPS Studio software (http://trl.trimble.com/dscgi/ds.py/Get/File-484972/TrimbleStudio.exe)
>
>However, when I connect via the RS232 port on the PicoSync I receive something that looks like a binary proprietary protocol that is not TSIP. I have been able to verify that the PicoSync also switches from from 9600-O-8-1 comm parameters from the internal Trimble Resolution T card to use 9600-N-8-1 on the RS232 output.
>
>I have used both oscilloscope connected directly to the Resolution T card via an TTL to RS232 converter as well as to the RS232 output and the signals looks ok with proper levels.
>
>It definitely looks like PicoSync is massaging the data in some way.
>
>This is how some of the HEX TSIP protocol data looks like coming out from the Trimble Resolution T card:
>Some of the Packet from the GPS receiver Trimble Resolution
>10 8F AB 00 06 5C 93 06 D5 00 10 00 23 30 13 12 07 07 DD 10 03
>10 6D 9C 3F F4 1C 23 3F 76 BF 16 3F D2 A3 88 3F 81 26 B2 1B 13 06 01 03 12 16 1C 0E 10 03
>10 5C 1B 00 01 01 40 D9 99 9A 48 CB 92 66 3F 51 45 76 40 3E 6E D8 00 00 00 01 10 03
>10 5C 13 08 01 01 40 A6 66 66 48 CB 92 66 3F 9A 88 DD 40 77 0A 03 00 00 00 01 10 03
>
>So that above looks like familiar TSIP packets with 0x10 as the starting byte and 0x10 and 0x03 as the ending bytes.
>
>At the same time the PicoSync outputs following packets on the RS232 output:
>02 04 00 00 00 42 6C B4 87 41 90 F6 5D 00 53 09 07 BC 3F 13 08 70 10 00 09 07 02 0D 06 05 01 00 FA 00 00 00 00 00 00 00 00 31
>
>02 04 00 00 00 42 6C B4 8A 41 90 F6 6B 00 50 09 07 BC 3F 13 09 E2 10 00 09 07 02 0D 06 05 01 00 FA 00 00 00 00 00 00 00 00 B2
>
>02 04 00 00 00 42 6C B4 8A 41 90 F6 6A 00 50 08 07 BC 3F 13 09 EE 10 00 09 07 02 0D 06 05 01 00 FA 00 00 00 00 00 00 00 00 BC
>
>02 04 00 00 00 42 6C B4 89 41 90 F6 69 00 51 09 07 BC 3F 13 0A 02 10 00 09 07 02 0D 06 05 01 00 FA 00 00 00 00 00 00 00 00 D1
>
>02 04 00 00 00 42 6C B4 89 41 90 F6 69 00 51 09 07 BC 3F 13 0A 04 10 00 09 07 02 0D 06 05 01 00 FA 00 00 00 00 00 00 00 00 D3
>
>Note that quite many initial bytes looks exactly similar between the transmissions and that the ending packets are also long and identical between the transmissions except for the final byte that seems to be some kind of counter counting up 0x02 on each transmission?
>
>I am pretty stuck now with trying to figure this out since I guess Fei-Zyfer Inc as well as Gillam-Fei in Belgium and Frequency Electronics Inc will probably not release any specs on the protocol being used. :(
>
>/Juha
>
>
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