[time-nuts] Symmetricom TimeSource 2700

[Bob Camp]

Hi

There are so many vendor / country specific sub (sub...sub) frames in T1/E1 that there must be at least one that sticks in time of day...

Bob

Sent from my iPhone

On Nov 23, 2011, at 7:01 PM, Mark Spencer <mspencer12345 at yahoo.ca> wrote:

> I'm curious if any one has any specific information about how TOD data could be sent via the native T1 data frames (as opposed to a signal which another piece of equipment could use as a clock source.)
> 
> I've never seen any specs for sending TOD information via the ESF Data Link or any other means, but that doesn't mean a spec doesn't exist somewhere.
> 
> --- On Mon, 11/21/11, Charles P. Steinmetz <charles_steinmetz at lavabit.com> wrote:
> 
>> From: Charles P. Steinmetz <charles_steinmetz at lavabit.com>
>> Subject: Re: [time-nuts] Symmetricom TimeSource 2700
>> To: "Discussion of precise time and frequency measurement" <time-nuts at febo.com>
>> Received: Monday, November 21, 2011, 6:13 PM
>> Kevin wrote:
>> 
>>> The PPS in/out of the PRS10 do not appear to connected
>> to the TS2700
>>> logic board.
>> 
>> I believe the TS2700 does not take PPS timing from the
>> PRS10, nor does it discipline the PRS10.  It does,
>> however, keep tabs on the frequency of the PRS10, and I
>> believe it uses this information to generate corrections to
>> the TS2700 frequency and timing outputs during holdover --
>> that is, I believe it does not just pass through the PRS10
>> 10 MHz signal and derive other timing signals from it during
>> holdover, but applies corrections that it has learned from
>> its monitoring.  See the block diagram at p. 19 of the
>> TS2700 manual and text at p. 14.
>> 
>>> I'm not looking for a
>>> PPS that's just a frequency/period reference, but
>> instead places the PPS
>>> at the GPS PPS position. Perhaps the TS2700 is already
>> do it, but so far,
>>> I've only seed evidence that it's a frequency
>> reference.
>> 
>> The whole point of the TS2700 is to be a Stratum 1 time
>> source.  See the TS2700 manual at pp. 14 and 113. 
>> The TS2700 clearly sends TOD information -- pretty much
>> every BTMon window contains a TOD display.
>> 
>> Because the TS2700 was designed for telecommunications
>> central office applications, the main outputs are two T1s,
>> "Span A" and "Span B," rather than computing protocols that
>> would be more familiar to most techies.  To access the
>> TOD and timing information, I think you would need to decode
>> the T1 data stream.  It may be available at the "Craft"
>> output, as well -- the TOD data definitely is, but I do not
>> know about the precision timing data.  (For those who
>> are curious, "Craft" is an ancient telecommunications
>> term.)
>> 
>> Best regards,
>> 
>> Charles
>> 
>> 
>> 
>> 
>> 
>> 
>> 
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> 
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