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Spirent TestCenter: How do I configure a Symmetricom XLi GPS receiver on a Spirent TestCenter chassis?


Spirent TestCenter chassis:

  • SPT-2U
  • SPT-3U
  • SPT-9U
  • SPT-11U
  • SPT-N11U
    Please note that the first release of the SPT-N11U chassis may not support an ETR device.

Symmetricom XLi GPS receiver


Instructions for installing the Symmetricom XLi GPS receiver on a Spirent TestCenter chassis:

1) The GPS antenna needs to be roof mounted with the following rules:

a) 360 degree line of sight to the sky
b) No obstructions (Buildings, trees, etc.) past 10 degrees from the base of the Antenna
c) Prefer not to extend the 75 Ohm BNC Coax cable, but if necessary use a high quality barrel connector (Not a T-Splitter) and make sure you use 75 Ohm (Not 50 Ohm) Coax Cable.

2) Connecting the cables and turn up the system

a) Extend the Coax to the XLi GPS receiver
b) Plug the Antenna into the ‘Antenna’ port
c) Power on the GPS Receiver.
Note:  You will notice that the receiver will say “Unlocked” and have a Time of Day “ToD” of xx:xx:xx:xx 1970.  It will take between 45 minutes and 24 hours to “Lock” to GPS time.

3) Telnet or console to the Spirent TestCenter chassis and login as 'admin' password is 'spt_admin'

a) Type in 'etr device XLI' <enter>    (this will force the chassis to only try to connect to an XLI device instead of searching thought different baud rates and commands etc)
b) Type in 'etr devname' <enter>    (this will verify that the change you just made is accepted by the chassis firmware

4) Plug the following in order:

a) Straight though (Not the cable included with the XLi, but the serial cable included with the Spirent TestCenter chassis) in the Serial port on the Symmetricom to the External Clock serial port (Not Console port)  on the Spirent TestCenter chassis.
b) Connect a BNC Cable from the 1PPS BNC port on the Symmetricom to the 1PPS port on the Spirent TestCenter
c) Connect (only after you have done a+b) a BNC Coax cable from 10 MHz BNC connector on the Spirent TestCenter Chassis to ‘J3’ port on the Symmetricom. 
    Note: The ‘J3’ Port is on the expansion card, not the ‘J3’ Connector on the XLi chassis. See the screenshot below that shows the expansion card.

5) Once you see the word “Locked” on the GPS receiver, then connect to the Spirent TestCenter chassis with the Spirent TestCenter GUI. Go to Tools>Equipment Information>Timing. Instead of clock source in the timing chain saying ‘Internal’ it should say ‘GPS’

6) Done.

Product : Chassis