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elnur.mammadov
Beginner

ASR9001 - GPS input for stratum-1 clocking

Hello,

 

which one of the many inputs and which receiver would you recommend for GPS.

Will this work?

http://www.microsemi.com/products/timing-synchronization-systems/accessories/communications/58534a-gps-timing-antenna

 

Thank you in advance

 

Regards

Elnur

 

1 ACCEPTED SOLUTION

Accepted Solutions
xthuijs
Cisco Employee

Hi Elnur,

GPS

- ToD (RS422 and RS232)

- 1-pps RS422 or 1.0/2.3 50-ohm RF connector

- 10MHz in/out 1.0/2.3 50-ohm RF connector

The GPS interface on RSP440 is supported. It needs all the three inputs i.e. ToD, 1pps and 10MHz.
 

You can use the spectracom, semitricon, but also this device you show seems to have the interface required for GPS 1pps reception.

Note that for the GPS interface to be perceived up, all 3 inputs are required. you can technically ignore the alarm for the TOD, but that requires then some syslog supressing etc.

If you are just only interested in frequency and not time, then I think cheapest is to have a GPS receiver with a BITS output (to either E1 or T1).

Also see more here in configs:

https://supportforums.cisco.com/document/133781/asr9000xr-frequency-synchronization
 

regards

xander

View solution in original post

11 REPLIES 11
xthuijs
Cisco Employee

Hi Elnur,

GPS

- ToD (RS422 and RS232)

- 1-pps RS422 or 1.0/2.3 50-ohm RF connector

- 10MHz in/out 1.0/2.3 50-ohm RF connector

The GPS interface on RSP440 is supported. It needs all the three inputs i.e. ToD, 1pps and 10MHz.
 

You can use the spectracom, semitricon, but also this device you show seems to have the interface required for GPS 1pps reception.

Note that for the GPS interface to be perceived up, all 3 inputs are required. you can technically ignore the alarm for the TOD, but that requires then some syslog supressing etc.

If you are just only interested in frequency and not time, then I think cheapest is to have a GPS receiver with a BITS output (to either E1 or T1).

Also see more here in configs:

https://supportforums.cisco.com/document/133781/asr9000xr-frequency-synchronization
 

regards

xander

View solution in original post

Thank you!

 

Rgds,

Elnur

Hello, and sorry for grave-digging this post, but I couldn't find an answer to the following question anywhere.

The question is: if a GPS timing antenna has only one output, and ASR 9K has three inputs for the GPS interface, what device should be used in-between - some kind of converter, perhaps?

Could you please give a hint about which manufacturer/model should I search for to buy this intermediary device?

Thanks for your time!

Hi Orkhan, the GPS input for the ASR9K is composed of 3 inputs:

frequency via the 10Mhz and 1pps and the RS422 for the TOD.

All 3 inputs are required to silence the alarm for gps input in the a9k sw, however we're working on allowing the 10M/1p inputs to operate without the TOD/rs422 input.

So when you say you only have 1 connection, I am a bit worried about this gps output you currently have.

cheers

xander

Thanks for the prompt reply!

I'm talking about a standard GRS antenna, like ones mentioned in the posts above:

1. Manufactured by Microsemi: http://www.microsemi.com/products/timing-synchronization-systems/accessories/communications/58534a-gps-timing-antenna

2. Manufactured by Spectracom:  http://www.spectracomcorp.com/ProductsServices/TimingSynchronization/GPSAntennasAccessories/8230GNSSAntenna/tabid/1630/Default.aspx

3. Manufactured by HP (Symmetricom): http://www.ebay.com/itm/HP-symmetricom-58534A-H01-GPS-timing-module-antenna-2-in1-receiver-/271687177124?pt=LH_DefaultDomain_0&hash=item3f41d153a4

4. Manufactured by others: http://www.ebay.com/sch/i.html?_from=R40&_trksid=p2050601.m570.l1313.TR0.TRC0.H0.Xgps+timing+antenna.TRS0&_nkw=gps+timing+antenna&_sacat=0

Maybe I'm missing something obvious, but I really can't understand how any of these can be connected to ASR 9K without an intermediary converter or another device.

Please give a clarification, if possible. Thanks in advance!

yup the part that you're missing is the converter box :)

this is just the antenna, you need a gps receiver tod/frequency converter to take the stuff from the antenna and provide the different signals with the right interfaces.

For A9K you need coaxial (small bnc) for 10mhz 1pps (freq) and rj45 with rs422 (tod).

converters as such as you can find here:

http://www.amt.com/mfrcatalog/symmetricom-satellite-uplink-downlink

cheers

xander

That explains a lot!

If i understand correctly, ASR 9K provides the clock itself when it has a GPS antenna connected, so even a very simple device, like this:

http://www.en4tel.com/pdfs/DS_TimeProvider_100.pdf 

will suffice?

Or it should be something more sophisticated, like this:

http://www.amt.com/images/products//DS_TimeProvider5000_AMT.pdf

But neither of these PDFs say that RJ45 output is with RS422... Maybe neither device is OK? Descriptions cause some confusion indeed...

OK, I think I will be able to figure out the details, but please give the last clarification.

Earlier in the topic you said that one of three interface should provide "ToD (RS422 and RS232)". But later you said "rj45 with rs422 (tod)".

Some devices (let's call them converters, although they seem to be more sophisticated and function-reach) have an output of RS-232, other devices have serial port described as "Serial I/O RS-232/422"... Can we stick with a device that has only RS-232 output, or it MUST support RS-422?

Thanks for your time!

for asr9k the rs422 is the only supported one, I never tested it with rs232, so I dont know if that works fine or not. if at all and your receiver has only a 232 connection, a simple converter box can easily be used to convert 232 to 422.

I would want to recommend 422 regardless however, simply because the standards dictate that 232, because of its asymmetric nature only has a very short reach, especially at higher bauds it can be affecting. 422 has a very long reach which might be useful in case your box is in one part of the area and your device in another.

also 422 can leverage cat5/6 cabling much more so then 232.

cheers!

xander

That was very helpful, thank you!

HI Xthuijs,

 In case that i am using ASR920 with only BITS port (RJ48C) and ToD/1-pps port (RJ45 with RS422).

How can I connect in order to get the three signals (10MHz, 1pps and ToD)? Additionally, which gps receiver tod/frequency converter do you recommend to use?.

Please check the attachment infomartion.

 

Thanks,

Marco Olacua