Another possible use is the freely configurable relay contacts, which can be remotely controlled via SIP or DTMF and thus help to integrate existing door opening systems, for example. High security standards, such as SHA 2 encryption, are key attributes of the PA1. Features. Public announcement system. Announcements in airports, trains and waiting lounges. Monitoring of securitysensitive environments. Remote maintenanceSpecifications. Weight 1.45 lbs