Audio-over-IP Interface

• All‑in‑one solution for audio transport on IP‑networks
• Supervised control inputs and outputs
• Supports re‑broadcasting
• EN 54‑16 compliant IP solution
• Configurable as SIP telephone interface (optional)

The PRS‑1AIP1 is a universal, IP‑based audio device supporting VoIP and Audio over IP applications. It is an ideal solution for bridging audio and contact closures over long distance LAN and WAN networks, e.g. in shopping malls, tunnels, in and between railway stations. It extends and interfaces to Praesideo and non‑network based traditional public address systems without the need for a PC during operation. The unit has analog audio inputs and outputs for easy interfacing with optional pilot‑tone supervision for emergency sound purposes. One audio input can be
switched to microphone sensitivity with built‑in microphone supervision. Also, the control inputs offer cable and connection supervision. Control inputs and outputs can be used to set up an audio connection to start a remote call, but also to pass remote fault events to the system controller.

SIP telephone interface
The PRS‑1AIP1 can be configured as a SIP telephone interface in combination with a PAVIRO public address
system. Details of the application is documented in the PAVIRO telephone interface application note.

Functions

Audio
Multiple audio formats are supported: single channel, full duplex 16‑bit PCM or G.711 for very low latency, and two-channel send or receive MP3 for high quality audio with various sample rates and compression settings. The unit provides two balanced line inputs and two balanced line outputs. One of the inputs can be configured as balanced microphone input with a phantom power supply for electret / condenser microphones and microphone connection supervision. The output level is configurable. Audio connection supervision using a 20 kHz pilot tone is supported, with detection on the audio input of the transmitter and regeneration on the audio output of the receiver.
A configurable audio delay can be used to artificially delay the playback of audio for loudspeaker alignment, e.g. in tunnels.

Audio Routing
Audio signals can be routed in uni‑cast to up to 16 receivers, preconfigured or on activation of control inputs. Receivers are able to re-broadcast the incoming audio stream to other receivers. In case the interfaces are on the same LAN also broadcast is supported. In PCM and G.711 (uLaw and aLaw) full duplex audio interfacing between two units is possible.

Control inputs and outputs
The unit has eight control inputs with configurable supervision on open and/or short-circuits. Eight control outputs have dry relay contacts. Control inputs can be routed to control outputs for remote actions or to pass on fault information between audio transmitter and receiver, in both directions. Control inputs can also be configured to change the audio routing. An additional dry relay contact is provided for fault indication of the unit, including a high temperature fault situation.

Network Interfaces
The unit interfaces to 10 and 100 Mbit Ethernet networks and announces its IP‑address that was given by a DHCP server. It can also search the network for a free IP‑address or can be given a static IP‑address. A second Ethernet connection is available to support network redundancy. An RS 232 interface is build‑in to communicate additional serial data over the IP network.

Power Supplies
Two power supply connections are provided as main input and backup input with supervision of both supplies.

Controls and Indicators (front)

• Reset button, recessed
• Two status indicator LEDs for network
• Eight status LEDs for control inputs

Interconnections (rear)

• Eight control inputs on Euro‑connector
• Eight control outputs on Euro‑connector
• Fault relay output on Euro‑connector
• Two balanced audio inputs on Euro‑connector (one line input, one line / microphone input)
• Two balanced audio outputs on Euro‑connector
• Two Ethernet connections on RJ45
• RS 232 on Sub‑D
• RS 485 on Euro‑connector
• Main power supply on jack
• Backup power supply on Euro‑connector