ADC Telecommunications Inc. SP0700LH Benutzerhandbuch

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ADCP-75-348 • Issue 1 • 04/2008
Page 21
© 2008, ADC Telecommunications, Inc.
6.9
EXT REF Connections
EXT REF connections between multiple HU’s is supported through two QMA type female 
connectors mounted on the System card. One of the jacks is designated as the IN port and the 
other jack is designated as the OUT port. The EXT REF interface allows HU’s to be connected 
together (in daisy-chain fashion) and clocked through a single source. Use the following 
procedure to connect EXT REF interface cables between multiple HU’s: 
1. Connect one end of the EXT REF interface cable (accessory) to either the IN or OUT port 
on HU #1 as shown in 
Figure 15. EXT REF Connections
2. Route the EXT REF interface cable to HU #2 and connect the cable’s free end to the port 
that is the logical opposite of the EXT REF interface connection at HU #1. 
Note: The HU SeRF SFP optical adapters are angled to the left. Therefore, pigtails should 
always be routed to the HU from the left side of the rack. Routing pigtails to the HU from 
the right side of the rack may exceed the bend radius limitations for the optical fiber. 
Note: When using the 10 MHz external reference clock the signal must be connected to 
the HU before enabling the clock source in the software.
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