 Systems which identify the caller's name and address to emergency telephone numbers (such as Enhanced 9-1-1 in North America) may be unable to identify which of multiple parties on a shared line placed a distress call; this is aggravated by the use of old mechanical switching equipment for party lines as this obsolete apparatus consistently provides no caller ID and often also lacks automatic number identification capability.When the party line was already in use, if any of the other subscribers to that line picked up the phone, they could hear and participate in the conversation.Eavesdropping opportunities abounded.