To make or keep safe from danger, attack, or harm: a vaccine to defend the body from infection. b. To engage in or be prepared to engage in battle to prevent (a population or area, for example) from being captured or occupied by an enemy.
Originally posted by voyager2: Excuse my lack of knowledge Nonsense! An MLO panel, as JW mentioned, stands for Main Lug Only. It is the opposite of an MDP, or Main Disconnect Panel. An MLO's busses and branch circuits are supplied by only the lugs at the line side of the panel, whereas an MDP provides overcurrent protection (OCPD) for the branch circuits.
FXO ports, like all the other analog interfaces, carry one call per port, so each RJ-11 port on your Cisco Unified CME router connects to one line from the PSTN and carries a single call at a time. A second call is given a busy tone if it tries to use the same port or line.