Networking Repeaters

Networking repeaters regenerate incoming electrical, wireless or optical signals to preserve signal integrity and extend the distance over which data can travel. With physical media such as Ethernet, data transmissions can travel only a limited distance before signal quality degrades. Consequently, networking repeaters are often used to connect cable segments in IEEE 802.3 networks, a standard developed by the Institute of Electrical and Electronic Engineers (IEEE) for Ethernet-based local area networks (LAN). In terms of the Open Systems Interconnection (OSI) model, networking repeaters are physical layer devices. Most high-level devices such as switches and routers do not incorporate the functions of networking repeaters. In wireless LAN (WLAN) or Wi-Fi networks, access points serve as repeaters only when operating in repeater mode. Some networking repeaters are stand-alone and enclosed. Others are integrated circuit (IC) chips or printed circuit boards (PCBs). Stackable, rack-mounted, hardened, full-duplex and wireless devices are also available. 

Selecting networking repeaters requires an analysis of network protocols. Examples include attached resource computer network (ARCNET), asynchronous transfer mode (ATM), controller area network bus (CANbus), control network (ControlNET), device network (DeviceNet), fiber distributed data interface (FDDI), Fibre Channel, frame relay, FOUNDATION Fieldbus, synchronous optical network (SONET), and token ring. Networking repeaters that use integrated services digital network (ISDN) and digital subscriber lines (xDSL) are also available. Voice over internet protocols (VOIP) include media gateway control protocol (MGCP), remote voice protocol (RVP), session announcement protocol (SAP), simple gateway control protocol (SGCP), session initiation protocol (SIP) and skinny client control protocol (SCCP). Most Ethernet networks use 10Base-T, 10Base-2, Fast Ethernet or Gigabit Ethernet. Several proprietary network protocols are available. Examples include AppleTalk^®, a registered trademark of Apple Computer, Inc.; INTERBUS^®, a registered trademark of Phoenix Contact GmbH & Co.; and PROFIBUS^®, a registered trademark of PROFIBUS International. 

Networking repeaters use several different connector types. Examples include attachment unit interface (AUI) connectors, Bayonet Neil-Concelman (BNC) connectors, medium interface connectors (MIC), RJ-45 connectors, straight tip (ST) connectors and subscription channel (SC) connectors. ISDN networking repeaters use either an S/T interface or a U interface. Serial RS232, RS422, and RS485 ports send data over a single wire. Universal serial bus (USB) is a 4-wire, 12-Mbps serial bus for low-to-medium speed peripheral device connections. T1 lines are dedicated phone connections that support data rates up to 1.544 Mbps. Fractional T1 does not use all of the 24 channels in a full T1 line. Similarly, fractional E1 does not use all of the 32 channels in a full E1 line, the European format for digital transmissions. T3 lines consist of 672 lines, each of which supports 64 kbps. E2 lines operate at 44 Mbps and can carry 672 channels of 64 kbps.

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