音频交换机(PAS)是由Willowglen Systems Inc.开发的,旨在为众多专用线路音频互连提供增强的可编程切换控制。PAS与4线E&M线路(例如为PABX干线提供的线路)连接,并将线路从任何输入切换到一个或多个输出。PAS支持许多操作功能,包括交换矩阵、广播、监视器、DTMF检测/发送和默认路由。开关矩阵功能用于将输入干线切换到输出干线。广播功能将一个输入连接到多个输出。监视器功能将两条PAS音频总线组合在一起,连接到扬声器或耳机听筒。使用监视器功能,多个扬声器可以监视同一音频。DTMF功能可在任何信道上进行DTMF检测和传输。对于DTMF检测,一次只能为每个中继接口模块分配一个信道。最后,默认路由将PABX中继线连接到相邻的默认线路,以防断电或通过命令。
AXIS P8221 Network I\/O Audio Module provides eight configurable input\/output (I\/O) ports and audio capabilities to a network video system that either does not have such support or require additional support. AXIS P8221 complements Axis network video products and integrates easily into existing network video installations using VAPIX®.","Sensors such as a door switch, smoke detector, IR detector or glass break detector—used for triggering an alarm event—can be connected as inputs. Output ports can be connected to control devices or relays, for instance, to open\/close doors or turn on\/off lights upon alarm.","AXIS P8221 supports two-way audio in half or full duplex. It has a built-in low power amplifier for small speakers so there is no need for an external preamplifier. It also has phantom power for a balanced microphone.","AXIS P8221 has support for Power over Ethernet allowing easy, cost-efficient and reliable installation.