Modem, NIC card And Network devices

Modem

•Do modulation

•D2A and A2D converter

•Mode+demod=modem

3 types of modems

•External  direct connect modem

•Internal direct connect modem

•Acoustic coupler modem

•External dcm are housed in external cabinet

•Internal dcm are plugged in pc slot or on board

•Fewer cables less expensive

•Both have own processor , storage, and communication circuit for dial , answer ,disconnect.

Effective

•Can tap into strength of different technologies.

•Combines features of multiple topologies.

•Fault tolerance from star

•Data reliability of ring

•Network extension of bus

•Simplicity of star

Network devices.

Node:

•Any device connected to a network

•Or

•Any device having IP address.

NIC card

•Used to connect to LAN

•May be designed for special type LAN or general LAN.