Camera means a device that renders an image of the outside world and then converts this image into a signal (e.g. video signal).
Beam axis means a line from the source through the centers of the x-ray fields.
Universal Digital Loop Carrier (UDLC) means the DLC system that has a CO terminal channel bank that is connected to the CO switches on the analog side.
CCTV means closed circuit television.
SPID is the number that identifies a service provider to the relevant NPAC. The SPID may be a state-specific number. "Serving Wire Center" denotes the CenturyLink building from which dial tone for local Exchange Service would normally be provided to a particular End User Customer premises. "Signaling System 7" or "SS7" is an out-of-band signaling protocol consisting of four basic sub- protocols: