The KLN-94 installation manual recommends the KI-202/206, KI-208A/209A, KPI-553A/553B, and the KI-525A as compatible indicators. However, most conventional nav indicators can provide the standard CDI interface for GPS lateral and/or vertical deviation. In most cases, there is already a nav indicator in most aircraft panels that is compatible with the GPS. Therefore, a means of switching the CDI between the nav and GPS sources is all that is needed. A good example of such a switching assembly would be a Mid-Continent MD-41.