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© 2006 Cisco Systems, Inc. All rights reserved.
Optimizing Converged Cisco Networks (ONT)
Lesson 1.1: The Evolution of Telephony in the Enterprise
© 2006 Cisco Systems, Inc. All rights reserved.
Objectives
Describe the history of the telephone services industry and its affect on modern business practices.
Identify the components of the traditional telephone system.
Describe traditional POTS service.
Describe ISDN & T1 services.
Explain the drivers of converged networks.
© 2006 Cisco Systems, Inc. All rights reserved.
Basic Telephone System
A telephone system has four elements: A telephone set to convert sound to electrical signals and back to sound
One or more central switching facilities
Connections to the central switching facilities
Connections among multiple switching centers across telephone networks
Subscribers connect to the telephone network using: Dedicated wire connections in overhead or underground cables
Radio waves (cellular, satellite, or radiotelephone)
VoIP
© 2006 Cisco Systems, Inc. All rights reserved.
Basic Components of a Modern Telephone System
Fiber
IP
POTS and ADSL
Central Office with Switches
Home Office with Corporate VPN including VoIP
Cellular Phone System
Long Distance and International Connections
Local Loop
© 2006 Cisco Systems, Inc. All rights reserved.
Traditional POTS Services
PSTN or PTT (POTS) has remained practically unchanged for over 100 years offering:
Bi-directional, or full duplex, voice path to carry sound both ways at once
Dial tone and ringing signals
Subscriber dialing
Operator services, such as directory assistance, long distance, and conference calling assistance
Power
© 2006 Cisco Systems, Inc. All rights reserved.
ISDN: A set of standards that allow data and voice to be carried on copper wire from the telephone exchange to customer premises:
BRI: 2 B-channels and 1 D-channel for control
PRI: 23 B-channels (30 in Europe) and 1 D-channel for control
T1 Carrier System: Specification for digital transmission between telephone exchanges and sometimes directly to customer premises. T1 uses copper wire or fiber.
ISDN and T1 Services
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Digital Telephone Services include:Voice mail
Caller ID
Call waiting
Reminder calls
(Three-way) conference calling
Enhanced 911 (in North America)
Centrex
A number of other similar services
Digital Telephone Services
© 2006 Cisco Systems, Inc. All rights reserved.
Centrex (a virtual PBX):Call Transfer
Call Divert – on no reply and on busy calls
Call Waiting
Three-Party Conference
Call Pick Up (Group)
Ring Back
Reminder or Alarm Call
Last Number Redial
Centrex Hotline (non-dialed connection)
Centrex Warm Line (delayed Hotline)
Centrex Hunt Groups, with optional bypass numbers
Typical Centrex telephone. Note the Recall button and the Message
Waiting lamp.
PBX and Centrex
© 2006 Cisco Systems, Inc. All rights reserved.
PBX
May I have a line to Chicago?
PSTN
Is this a business call?
Thank you. One second please.
Chicago Office
Yes it is.
Long-Distance Calling Challenges
© 2006 Cisco Systems, Inc. All rights reserved.
Long-distance trunk lines connect telephone exchanges.
Long-distance services include:OUT-WATS: Flat-rate long-distance calling
IN-WATS: Toll-free calling using 1-8xx numbers
Long-Distance and WATS
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San Jose Office
Tokyo Office
London Office
PBX
PBXPBX
Separate Voice, Video, and Data Networks
© 2006 Cisco Systems, Inc. All rights reserved.
IP WAN
PSTN
Converged Voice, Video, and Data Network
© 2006 Cisco Systems, Inc. All rights reserved.
Self Check
1. What are the 2 levels of ISDN service?
2. What is a Centrex?
3. What is a WATS-type plan?
4. What options are available in WATS plans?
© 2006 Cisco Systems, Inc. All rights reserved.
Summary
Companies have used telephone services for over 100 years as a part of their business practices.
Changing technology and changing enterprise needs have influenced changes in telephony services.
The increasing use of IP transport for data, voice and video has lead to the need for converged networks.
© 2006 Cisco Systems, Inc. All rights reserved.
Q and A
© 2006 Cisco Systems, Inc. All rights reserved.
Resources
Wikipedia Telephone Exchange articlehttp://en.wikipedia.org/wiki/Telephone_exchange
Cisco IP Telephones on Converged Network Enable Rapid Emergency Response
http://newsroom.cisco.com/dlls/partners/success_stories/2001/pss_10-10.html
Making the Business Case for Unified Communicationshttp://www.cisco.com/en/US/netsol/ns340/ns394/ns165/networking_solutions_audience_business_benefit0900aecd80472efb.html
© 2006 Cisco Systems, Inc. All rights reserved.