This post is an introduction to topics related to communications technology.
Signal Processing
You can read this post about signal processing.
Wired Communications
Telecommunication Cabling
Power Line Communications (PLC) filters the electric signal by frequency.
Communication Network Technologies
Communication technologies:
- POTS with dial-up Internet access
- ISDN
- xDSL
- DOCSIS
POTS with dial-up Internet access
Plain old telephone system (POTS) or plain ordinary telephone system were the communication system traditionally used to make telephone calls.
POTS combined with dial-up internet access was the first method for communication technologies.
ISDN
Integrated Services Digital Network (ISDN) is a set of communication standards for simultaneous digital transmission of voice, video, data, and other network services over the digitalised circuits of the public switched telephone network.
xDSL
Digital Subscriber Line (DSL) is a family of technologies to provide digital data over telephone lines.
There are different types of xDSL technologies:
- ADSL
- VDSL
- DDSL
DOCSIS
DOCSIS is an standard to exchange data over the TV cable.
You can read this post about DOCSIS.
Wireless Communications
You can read this post about wireless communication.
Take into account that wireless communications does not imply mobility, i.e., connecting from different places using the same system.
Mobile Communications
You can read this post about mobile communications.
Network Convergence
Topics related to network convergence:
- Videoconferencing
- Video streaming
- NGN
- IoT
- FMC
- Unified Communications
Videoconferencing
Videoconferencing are point-to-point (1:1) or multipoint (n:m).
You can read a post about videoconferencing.
Video Streaming
Video Streaming are 1:n
Video streaming uses the following protocols:
- MMS
- RTSP
- RTP
- HLS
- MPEG-DASH
NGN
A Next Generation Network (NGN) transports all information and services (voice, data, and all sorts of media such as video) by encapsulating these into IP packets, similar to those used on the Internet.
NGN are based on IP and MPLS at network level and Session Initiation Protocol (SIP) and H.323 at application level.
IoT
Internet of Things (IoT)
You can read this post about IoT.
Fixed-mobile Convergence
Fixed-mobile convergence (FMC) is a change in telecommunications that removes differences between fixed and mobile networks.
Unified Communications
Unified communications (UC) is a business and marketing concept describing the integration of enterprise communication services.
Erlang Calculation
The erlang is a dimensionless unit that is used in telephony as a measure of offered load on service-providing elements
A = N * T
where
A is the total amount of erlangs
N is the number of server (such as the number of telephone units).
T is the average occupation.
There is an Erlang-B formula that takes into consideration the blocking probability.
Telecommunications Organizations
ITU
International Telecommunication Union (ITU) belongs to the United Nations (UN).
ITU sectors or branches:
- ITU-R
- ITU-T
- ITU-D
ITU Radio (ITU-R)
ITU Telecommunication Standardization (ITU-T)
ITU Development (ITU-D)
ITU organizes the standards based in groups identified by a letter:
- H: Multimedia and audiovisual systems