Modems Flashcards
What does modem stand for ?
Modulator demodulator
What is a modem used for ?
To convert analogue into digital.
Two types of modems they are ?
Serials modems and parallel modems.
What is a serial modem ?
A serial modem transmits and receives one bit of data at a time
What is a parallel modem ?
A parallel modem transmits and receives data on a number of levels at the same time.
What are he advantages of serial modems ?
Reduction of cable size (less expensive )
No requirement for synchronisation
Disadavantges of serial modems?
Slower transmission times
Advantages of parallel modems ?
Can send a bulk of data compared to serial modems.
Disadvantages of parallel modems ?
Requires an internal clock to maintain synchronicity
Requires a signalling command to transmit data
Where are modems employed?
Used to convey digital data between transmit and receive terminals
What are the 5 types of modems ?
Narrowband/phone dial up, radio modems, wifi/WiMAX, mobile and router modems and broadband.
What are the two modes that a narrowband modem can be in ?
Data mode and command mode.
Where are radio modems usually employed ?
They are employed for use in high speed computer network links where laying cables would be uneconomical.
Wireless data modems where are they used ?
Wifi and WiMAX.
What advantages does WiMAX have over wifi?
Faster speeds at greater distances.
