IDC (Insulation Displacing Connectors) termination is the preferred method for terminating wires for voice or data connectivity; such as 66 blocks and 110 systems. Cablesys insists on IDC termination for connecting Telco connectors to a 25-pair cable because the connections have excellent performance and high reliability. The terminals have spring properties that hold the wires in a stable mechanical condition.
Manual soldering can be inconsistent and subject to failure as a result of mechanical or temperature stresses. A cold-soldered joint is caused by improper heating of solder may not conduct at all or only intermittently. An overheated solder will burn the flux, destroy its effectiveness and the solder will not enter the joint properly. A dry joint is caused by movement during the soldering process which can develop cracks in the jointed area leading to intermittent conductivity. Many solders still contain lead which is hazardous to the environment.