A method and apparatus for handling persistence measurement of channel associated signaling for a plurality of line circuits, eg, T1, E1, OC3, STM 1 circuits, which extracts channel associated signaling data from a plurality of line circuits; assembles the channel associated signaling data into a data frame; contains the data frame in a suitable carrier, eg, an AAL 0 cell; monitors a continuous stream of the data frames, to check for changes in line status; and generates an event message data frame when a persistent change of line state has been detected. The extracting of associated signaling data may be provided on a separate card to a call control processor, and using separate processor functionality. A data processing load of a prior art call control processor which would otherwise be taken up in channel associated signaling persistence measurements may be alleviated, and the data processing burden on a prior art call control processor for handling persistence measurements is separated off and handled by the data processing apparatus and method according to the present disclosure.