RCA 70/700 Series Reference Manual page 109

Controls and Indicators
70/725 Data Gathering
System Buffer
• The operator's controls and indicators for the DGS Buffer are located
on the CCM Control Panel. They consist of the following:
Data (indicator) -
This indicator is lighted whenever the buffer
is receiving data signals from an DGS Input Station.
Select (patch panel) -
The buffer is easily connected to any CCM
Select (SEL) line, and is thereby enabled if power is on. When the
buffer is enabled, it responds to each SEL with BOP.
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