Voice Communications for 911 Personnel

New Admin

10 years ago

Introduction: Why Should a PSAP Care?
Overview
Family Tree of Telephony
- Conventional Calls
- Cellular/Wireless
- VoIP
  - Fixed
  - Nomadic
  - Mobile/802.x
  - Hybrid Cellular/802.x
Technical Background
- Analog Transmission
- Digital Transmission
  - Binary Number System
  - Binary Encoding: Hand Codes, ASCII
- Circuits
  - Bit Path
  - Timing
  - Synchronization
- Time Division Multiplexing
  - T1/DS1
  - Framing/Frame Format
  - Time Slots
  - PSAP Capacity
- Packet Switching
  - Packet Format: Header, Payload, Trailer
  - IP
  - Packet QoS/QoE
  - Best Effort
Transmission of Human Speech
- Human/Musical Instrument Model
- Analog
- Digital
  - PCM
  - LPC
- Loss
  - Packet Loss
  - Sample Loss
  - Coding Loss
911 End-to-End
- Conventional
- Cellular/Wireless
- VoIP: NENA I1, NENA I2, NENA I3
- VoIP Protocol
- PSAP Procedures
MSAG and Location Issues
VoIP Issues
- Lack of Hand-offs
- VoIP Is Not Traditional Telephony, Just Cheaper.
- Inconsistent Call Routing
- Missing or Inaccurate ANI/ALI
- Voice Quality Ranges Substantially.
- Misinterpretation of Whispers, Soft Sounds, and Background Noise
- Non-transmission of Whispers, Soft Sounds, and Background Noise
- Misinterpretation of Non-Human Sounds
- Quality Degradation during Heavy Call Volumes
- Evidentiary Issues Related to Recordings of VoIP Calls
- Power Failure and Battery-Backup Option, Does Not Work During Power Outages
- Use of Mobile Wireless VoIP and Location Issues
- Fraudulent and Misleading Use of VoIP – Bombing and SWATing
- Lack of Clarity in VoIP Standards
- Training on IP, VoIP and Related Technologies
- PSAP Best Practices