3 - 12 Chapter 3Chapter 3 - Installing Extensions and TrunksSECTION 3-10INSTALLING A DID CHOKE3.10.1 DID ChokeIf your central office has a high level of AC noise or if your site is experiencing excessive hum on the DID lines,a customer-provided isolation transformer can be installed between the UX5000 and telco blocks to help tosuppress the hum.DID trunks must be bridged from the telco RJ21X to a line cross-connect (A) block. The choke is installedbetween these two blocks.DID Choke Installation:1. Remove the bridging clips on the (A) block and telco block for the DID lines.2. From the telco block, solder the Tip lead to the “3” connector on the choke.3. From the telco block, take the Ring lead and solder it to the “1” connector on the choke.4. From the (A) block, take the Tip 1 lead and solder it to the “4” connector on the choke.5. Solder the Ring 1 lead from the (A) block to the “2” connector on the choke.6. Reinstall the bridging clips as required.
