APPLICATIONS
In its simplest form, the R165A is nothing more than a multi-contact relay capable of switching away
from signal A and connecting to signal B. There are 4 independent relay sections in each R165A. All
sections of the relay are of the mechanical type with no active circuitry involved in the signal path.
Each relay in the R165A is internally divided into 2 sections – video and audio. The video section is
constructed so that its reference impedance is 75 ohms. The relay used here is a high quality RF
type so that the video section can also be used for switching RF signals up to 950 MHz (see
specifications). It should be noted that the non-selected input into the video section is terminated into
75 ohms.
The audio section has contacts enough to provide full balanced stereo audio. In addition, there are
also 2 sets of auxiliary contacts for switching additional signals such as SAP or various tally
indicators. Check specifications for ratings on these contacts. A basic schematic of one of the four
relays is shown in the following graphic.
Activation of any of the 4 relays can be accomplished by external contact closure, open collector
transistor or logic signal. In most applications, the R165A is connected to other devices that provide
the activation signal. The most popular applications for controlling the R165A are time control, LAN
