cordless systems

GROUP 3:Name: Reg#:Paschal, Privatus 2011-04-05855Richard, Evarist S 2011-04-00142Nyakia,Thomas 2011-04-02271Mchwampaka Davies 2011-04-03213Urassa Richard E 2011-04-00697Reuben, Elisha 2011-04-05998

04/15/23 TE412 : GROUP 3, CORDLESS SYSTEM 1

CORDLESS means lacking a cord so cordless of an electrical/electronic appliance means that

appliance requiring no wire leading to an external electricity source because of a self contained power supply i.e. powered by an internal battery

E.g cordless telephone

Cordless telephone is a telephone with a wireless handset that communicates via radio waves with a base station connected to a fixed telephone line, usually within a limited range of its base station (which has the handset cradle).

There are various generations of cordless system CT0,CT1,CT2,CT3,DECT,PHP.,PACS,PCS and PWTS


PSTNFixed Port (Base Station)

Wireless Link

Cordless Handset

CORDLESS SYSTEM CONFIGURATION


• An early standard for analog cordless telephony developed in Europe. Originally CT0

Features; Operates in the 916MHz and

960MHz bands over paired channels 25 kHz wide and employs Frequency modulation (FM).

FDMA and FDD are used to derive two separate channels, one downstream and one upstream each of which is 12.5 kHz wide.


•Limited in range to approximately 150m.•It lacks security•CT1+ was intended as the basis for public wireless service along lines of telepoint which operates in the 887MHz and 932MHz bands over 80 channels 25 kHz wide with one channel per carrier.•CT1+ employs FDMA and FDD

• It employs TDMA and TDD• It was originally supporting only

outgoing calls, • Contemporary CT2

implementations support two way calling

• Does not support handoff, so the user must remain within the range of the antenna used to set up the call

• 10 mW maximum power output• It uses Gaussian filtered GMSK• Up to 100 meter (300 ft) range• CT2 operates in the 864-

868MHz• CT2+, this is an improvement

of CT2 supporting two way calling and call hand-off which uses 8MHz in the rang 944MHz to 952MHz.


•A proprietary digital cordless telephone system developed by Ericsson in 1990 as a wireless office telecommunication system (WOTS) for application in high-density office environments that also bases on TDMA and TDD at approximately 8MHz bandwidth starting from 944MHz.

CT-2 CT-3

• Typical CT users were sold a handset and base station which they could connect to their own home telephone system. Calls via the home base station would be routed via the home telephone line and in this configuration, the system was identical to a standard cordless phone. When in range, the user could receive incoming calls.

• E.g In CT-2, when in range user could receive incoming calls and once out of range, the CT2 user could find signs indicating a network base station in the area, and make outgoing calls (but not receive calls) using the network base station.


Japanese air interface standard developed by the Research and Development Centre for Radio Systems (RCR). The PHS network interface was specified by the Telecommunications Technical Committee of Japan.

It offers two –way communications, data services and Internet services.


•PHS cells are small with transmission power of base station a maximum of 500 mW and coverage about 2km in LOS•Uses TDMA/TDD for its radio channel access method, •Pi/4 DQPSK modulation at a channel rate of 384kbps is used on both forward and backward links.

• Has capability to handover from one cell to another. This makes PHS suitable for dense urban areas, but impractical for rural areas, and the small cell size also makes it difficult if not impossible to make calls from rapidly moving vehicles.

• It supports seventy-seven radio channels, each 300 kHz wide. Forty of the channels are designated for public systems, and the other thirty-seven are used for home or office use.

• It has low-cost base stations, and it supports "Dynamic Cell Assignment" system,

• Modern PHS phone support many value-added services such as high speed wireless data/ Internet connection (64 kbit/s and higher), WWW access, e-mailing, text messaging and even color image transfer.


• Were published in 1992. The name has been replaced by Digital Enhanced Coreless Telephone .

• DECT is also based on TDMA/TDD. • DECT is typically implemented as a

wireless-PBX connected to the PSTN.• it is free wireless operates around 100

meters outdoor and much less indoor around 50 meters

• Offers both speech and relatively high data rate transmission capability (<300 kb/s).


• It transmit a signal during the time slot allocated to it.

• Transmitting signal during the idle time allows remote handset to remain synchronized and be able to receive a call immediately.

• Output power is around 2mW in idle mode


• The handset does not transmit at all during the idle periods.

• The transmitted power which results is around 9.5mW in active mode (during calls) and virtually zero in idle mode (most of the time).

BASE STATIONHANDSET

• Residential- one base station can be used to provide in house voice and data transfer

• Officesmall office can be serviced by one base

station.Multiple base stations can be configured to

support large office.• Tele-point also set up for the public

places like in airports


2G Digital Cordless specifications


There are very few homes in Tanzania that use CT2 system due to decline (poor infrastructure) of landline trunks.

DECT is much used in many offices like Bank, Industries and companies.

PHS Declined due to decreasing costs of full cellular service.


cordless systems

Engineering