AT-S7/AT-S9 Operations Manual
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STAND-ALONE—Repeater operating as a hub on its own; i.e., not a module among other
modules in a department concentrator chassis.
STRAIGHT-THROUGH—
A type of wiring connection where the pins of one
connector connect to the same pins of another connector. For example, pin 1 of one
connector connects to pin 1 of another connector.
STRAIGHT TIP (ST) CONNECTOR—
A type of port connection where the pins
connect through a bayonet-style interface.
SUBSCRIBER CHANNEL (SC) CONNECTOR—
A type of port connection where
the pins connect through a push-pull mating interface.
SUB MINIATURE ASSEMBLY (SMA) CONNECTOR
—
A type of port connection
where the pins connect through a threaded attachment interface. Also referred to
as an SM Connector.
SWITCH, ETHERNET—A type of Ethernet hub that filters traffic based on low-level
address. As over against a repeater, a switch does not necessarily broadcast, retime or
retransmit packets, depending on its configuration. A switch cuts down on traffic by placing
packets only on the receiver’s segment when known.
SWITCHED VIRTUAL CIRCUIT (SVC)—A virtual circuit (X.25), virtual connection
(Frame Relay) or virtual channel connection (ATM) that has been established dynamically
in response to a signaling request message.
SWITCHED LAN—Emerging technology that replaces the shared bus backplane of
Ethernet hubs and the shared ring backplane of token Ring hubs with a switching
backplane. Connectivity is provided by switching sender traffic directly to the port of the
addressed destination device. Provides potentially higher throughput, scalable capacity,
and simpler configuration support. Does not require any changes to access wiring or adapter
cards.
SYNCHRONOUS OPTICAL NETWORK (SONET)—A set of physical layer definitions
for data transmission across fiber-based high-speed links. Two options are available for the
Fiber Optic ATM interface: Synchronous Optical Network (SONET) STS-3c-type framing
(which is more common in North America) and Synchronous Digital Hierarchy (SDH-1)
framing (which is more common in other countries). Whichever option you choose should
remain consistent throughout the entire network.
TCP/IP PROTOCOLS—A set of protocols for intercomputer communication, including
network level (Internet Protocol), transport level (Transmission Control Protocol or TCP)
and application level protocols (for example, Telnet terminal emulation). TCP/IP has been
used for many years in two country-wide networks, the ARPANET and MILNET.
Recently, TCP/IP has become very popular with users of a variety of multi-user computer
systems and engineering workstations. Most UNIX computers use TCP/IP over Ethernet
as the main intercomputer networking technology. TCP/IP is also popular among PC users,
particularly as a means of communication with large multi-user computers.
TIME DIVISION MULTIPLEXING (TDM) — This is a technique that combines several
channels onto one high-speed circuit by providing each channel a specific, regularly
recurring time slot sufficsient to carry the full transmission rate of that channel. The
transmixsion rate of the the high-speed circuit must be equal to, or greater than, the
aggregate speed of all of the channels.
TELCO CONNECTOR— A 50-pin receptacle that plugs into the front of the hub, enabling
cables from external devices to connect to the hub.
TRUNK CABLE—Coaxial cable used for distribution of signals over long distances
throughout a cable system.
UNSHIELDED TWISTED PAIR (UTP)—A cable used in 10BASE-T wiring that consists
of at least two twisted pairs of 22 to 26 AWG wire. The pairs should have at least 3 twists
per foot and have an impedance of 100 W. Level 3, Level 4 and Level 5 UTP cables fit these
criteria.
