Spec Sheet Preview: The Alpha Communications® / TekTone OF20_ series panel and annunciator frames are made of heavy gauge extruded aluminum, in a natural (clear) anodized finish. They are used primarily with nurse-call and emergency-call annunciator master stations, but are also used with a variety of apartment entry intercom and video intercom lobby panel modules. For flush mounting, the OF20_ series can be used by itself, or with the matching OH20_ series flush back box/housing. For surface mounting, the OF2 …