This type of coupler is compatible with SA-3 and Willison couplers. These include EDF, fused-fibre optical couplers and optical isolators. Directional couplers or two resistor power dividers are used for signal separation. Installation of couplers and tapping tee fittings require slightly different procedures. Such devices include impedance matching components, directional couplers, and diplexers. Directional couplers and power dividers have many applications. A defined flange that can have any of several of the above couplers installed. Similar comments can be made regarding power dividers and directional couplers. The forward and reflected power measured by directional couplers can be used to calculate SWR. The basic components of scaffolding are tubes, couplers and boards. The symbols most often used for directional couplers are shown in figure 1. On the other hand, incident and reflected power are easy to measure using directional couplers. Early modems were generally very simple devices using acoustic couplers to handle telephone operation. The same is true for cables and couplers inside the network analyzer. Registered jacks replaced the use of protective couplers provided exclusively by the telephone company.