Raspberry Pi SIP Speaker Development

I'm looking for a skilled developer to create a SIP speaker using Raspberry Pi and an analog speaker. The device should support two-way audio communication and IP paging.

Key requirements:
- Use Raspberry Pi as the main hardware platform
- Implement two-way audio communication
- Enable IP paging functionality
- Support SIP, IAX, and WebRTC protocols

Ideal skills and experience:
- Proficiency in Raspberry Pi development
- Experience with SIP, IAX, and WebRTC protocols
- Knowledge in audio processing and two-way communication systems
- Ability to configure and implement IP paging

Please provide samples of similar work done and a brief outline of your approach.