DUE Telephone /VoIP Learning Activity 4 Learning Outcomes 1 and 5

Telephony / VoIP Differentiate and describe POTS vs. VoIP delivery. Identify and troubleshoot common issues.

Telephony / VoIP Analog 1. Plain Old Telephone Service (POTS) 2. Most home telephones still use analog devices connected to analog phone lines 3. Signals move relatively slowly when carried in physical media such as copper wire and cable

Telephone Subsystem Delivers telephone services to home Design follows local codes and standards Demarcation  Telephone enters home  Service distributed to home  SP responsibility stops

Low-Voltage Telephone  Cat 3 FCC required minimum for phone lines Older homes  Cat 5 Newer constructions Recommended by ANSI/TIA/EIA-570-A  Scalable  Expanded for VoIP

Tip and Ring Early telephone  Switchboard plugs inserted into receptacle Tip of plug = 1 conductor Ring = other conductor “Tip and Ring”  Colors of Tip White Red Black Yellow Violet  Colors of Ring Blue Orange Green Brown

Wire Pairs and Color Codes 4 Pair cable such as CAT 5  Primary color is tip = white with tracer White wire = tip = first wire of pair to be punched down  Ring = Solid color Wire Pairs  Pair 1 - Blue White/Blue Blue  Pair 2 - Orange White/Orange Orange  Pair 3 – Green White/Green Green  Pair 4 White/Brown Brown

Telephony / VoIP Frequency Division Multiplexing 1. The process of allowing analog lines the capability to carry multiple conversations or data streams at the same time. 2. Made possible by dividing analog frequencies on a line and sharing them among different voice and data lines 3. Multiple telephone lines are possible on home and businesses without the additional cost of adding more wires.

Telephony / VoIP Centrex System Central Switching Exchange, used by organizations having telephones in many locations A telephone line would have many extensions, but only one call could be made at a time.

Telephony / VoIP VoIP Data (Packets) are moved via Internet Protocol (IP) from LAN to LAN.  Voice can travel on same LAN network.  Systems require special hardware, configuration and settings in quality to meet the same standards set forth by the Telephone System.

Telephony / VoIP Voice over IP (VoIP) Packets must be received and reassembled into the order they were sent, voice decoded from digital to analog and sent to the phone speaker, all without any time lags or delays.

Telephony / VoIP Digital Faster data/voice transfer rates Packets are used as the transport of digital signals Use Protocols to set standards, … i. e. Addressing, Errors, Control Uses zeros and ones, making it easy to read and duplicate

Telephony / VoIP Soft phones An application (software) written to act as a telephone with a computer. The soft phone: Displays phone features Hold Button Caller ID Message waiting light Other features Routes calls with use of a headset or special (USB) phone connection Works with minimum PC hardware requirements Provides same functionality as the PC. (Remote, mobility)

Telephony / VoIP POTS 1. Cross talk 2. Radio interference 3. Dead ports 4. REN (Ringer Equivalence Number)

Telephony / VoIP Crosstalk:..speech or signaling tones leaking from other people's connections..a signal affecting another nearby signal

Telephony / VoIP Radio Interference:..disturbance caused in a radio receiver or other electrical circuit by electromagnetic radiation emitted from an external source

Telephony / VoIP Ringer Equivalence Number (REN)..a somewhat arbitrary number which denotes the electrical load a telephone ringer has on the line REN – in the US considered a yardstick

Telephony / VoIP PBX Private Lines Switch System Usually is considered the demarcation point or demark between the owner and the Telephone Company. A device used to route calls from the owners equipment (PBX) to the public telephone system

Telephony / VoIP Describe and define fundamentals of telephone systems

Troubleshooting Steps to troubleshoot problems  Observe symptoms  Isolate cause  Check connections  Test hardware  Test software

Troubleshooting Telephones Possible Telephone problems: Inconsistent ringing of phone, Can not hear / or be heard, Dialing wrong number Solutions: The handset, the telephone base, wiring, or Telephone Co. (software)

Troubleshooting Telephones Solutions: -- Make sure phone is working, -- Connect in several phone jacks -- Check for a dial tone

Troubleshooting Telephones Power Limits: The phone has a limited amount of power available from the phone company to make your phones ring Solution: Exceeded REN - Remove a phone.

Troubleshooting VoIP VoIP – Telephones The phone does not work. Solution: No Power No IP address Software issues

Telephone vs. VoIP: Summary o The Analog Telephone System (POTS) has been in existence for over 130 years. o Digital Telephone Transmission has improved voice quality and added other special features. o The Public Switched Telephone Network provided a central exchange of connecting private networks to the public network. o Digital Telephone transmission is being expanded into the Internet as VoIP. o The analog telephone is still used in many households. o The analog telephone is a voice device with a speaker, microphone, and digital keypad.

Telephone vs. VoIP: Summary Telephone: Old Technology Reliable Good Sound Quality Relative Inexpensive VoIP: New Technology Becoming popular Many added features Lower cost

Questions and Contacts Julian Carranza, Eliazar Martinez, This material is based upon work supported by the National Science Foundation under Grant No Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation