In land-line telephony, AIOD leads are Terminal equipment leads used solely to transmit (AIOD) data from a PBX to the public switched telephone network or to switched service networks (e.g., EPSCS), so that a vendor can provide a detailed monthly bill identifying long distance calling usage by individual PBX stations, tie trunks, or the . It resembles common channel signalling in that the AIOD leads provide data for all trunks, but is used only for billing, thus resembling automatic number identification.