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technician101 · April 26th, 2005, 02:33 PM

More than once I have had the pairs reversed by the telco, loopback testing will work but circuit will not come up. Make a reversing cable with one end 568B and the other 568B with blue (pins 4&5) and orange (pins 1&2) pairs reversed. You stated that you placed test calls, did you have to reverse your connections to your test unit?

April 26th, 2005, 02:33 PM	#11 (permalink)
technician101 PBXtech SILVER 25+ posts Join Date: May 2004 Posts: 33	Re: ISDN PRI Won't come up More than once I have had the pairs reversed by the telco, loopback testing will work but circuit will not come up. Make a reversing cable with one end 568B and the other 568B with blue (pins 4&5) and orange (pins 1&2) pairs reversed. You stated that you placed test calls, did you have to reverse your connections to your test unit?