Modem Allows modems of different vendors to operate together Define How modems operate: Modulation techniques Data compression technique Error detection strategy
Modem – Analog vs Digital Analog Infinite number of levels Conform to voice pattern Times from highest to lowest and back to the highest point in one second is the frequency Can be transmitted over long distance Digital Only two levels (high and low) Conforms to how computers operate Cannot transmitted over long distance
DVB – DVB/IP Tech The Digital Video Broadcast over Internet Protocol (DVB/IP) system is functionally an IP-over-Ethernet simplex satellite service that incorporates frame-relay type traffic management. At its core, DVB is a modem- on-a-chip, plus an intelligent multiplexer. The antenna is typically a CATV dish, 2.4 - 3.8 meters in diameter (for C-band), or 0.6 - 1.8 meters (for Ku-band).
Twisted Pair Two wired wrapped in a twisted fashion Designed to reduce cross-talk due inductance Still subject to interference from stray signal Primarily used for local loop connections and LANs Comparatively narrow bandwidth
UTP - Category CategoryMaximum Data RateUsual Application CAT 1Less than 1 MbpsAnalog voice (POTS), Integrated Services Digital Network Basic Rate Interface in ISDN Doorbell wiring CAT 24 MbpsMainly used in the IBM Cabling System for token ring networks CAT 316 MbpsVoice and data on 10BASE-T Ethernet CAT 420 MbpsUsed in 16 Mbps Token Ring Otherwise not used much CAT 5100 Mbps100 Mbps TPDDI (100BASE-T or Fast Ethernet) 1000 Mbps (4 pair)155 Mbps ATM Gigabit Ethernet CAT 5E100 Mbps100 Mbps TPDDI (100BASE-T or Fast Ethernet) 155 Mbps ATM CAT 6200-250 MHzSuper-fast Broadband Applications.
Coaxial Center lead conducts the signal Protected by insulation and braded wire Used mostly for television and connections to antenna Larger Bandwidth but large in size
Jenis Medium Coaxial cable RG-58 (10BASE2) BASEBAND Panjang max tanpa cacat 10 Mbit/s
Fiber Optical Signal transmitted by photos rather than electrons Dramatically higher bandwidth Used mostly for backbone communication connections, very high speed LANs and fast network connections
Hub versus Switch Hub provide connection to all ports (i.e. in one port and out all other ports). Passive hub – no signal regeneration Active hub – provide signal regeneration Switch direct the message from appropriate port (directs a message from the input port to the desired output port). More expensive but better bandwidth utilization