通常在公共场合发布通知需要设立专门广播站,插报通知的人需到广播站进行,极不方便,而且效率很低。在国外某些场合如飞机场、车站等,有许多是利用电话线控制功率放大器播发通知,使用相当灵活。将一电话号码分配给此功放,只要内部人员牢记此号,均可通过电话直接播报通知,而不知此号的局外人员也无法使用该系统。根据以 It is often inconvenient and inefficient to issue a notice in public, which usually requires setting up a dedicated radio station, to those who broadcast the notice. In some foreign occasions, such as airports, stations, etc., many are using the phone line control amplifier broadcast notification, the use of a very flexible. Assigning a phone number to this amplifier allows announcements to be made directly by phone, as long as insiders keep this number in mind, without the knowledge that outsiders of that number will not be able to use the system. According to