Digi 90031300 manual T1 Modem Bank

network ¾ a collection of links, nodes, and computers that provide connections between two or more defined points to facilitate telecommunication between them.

off-hook¾ the modem is in use, and the activity light is on.

PCM (Pulse Code Modulation) ¾ the standard digital voice format, at 64K bps;

POP (Point-of-Presence) ¾ the point within a local TELCO where the subscribers’ circuits for leased-line or long distance dialup circuits are terminated.

PPP(Point-to-point protocol) ¾ a communication link in which two stations are directly connected. PPP allows for TCP/IP connections over serial lines and serial devices such as modems.

Private or leased lines ¾ refer to a permanent circuit between endpoints over which data is transmitted. Private or leased circuits are available from providers of WAN digital communications. T1 lines can be supplied by the provider to include private or leased circuits and others such as switched lines.

Protocol ¾ a set of rules or standards designed to enable computers to connect with one another and exchange information with as few errors as possible.

PSTN (Public Switched Telephone Network)

Robbed bit signaling ¾ a bit in the data stream used for signaling

switched line ¾ a single-circuit line connection between two points on a switched network. This is usually a connection made as a result of dialing via the phone system, as opposed to a permanent leased line.

TCP/IP (Transmission Control Protocol/Internet Protocol) ¾ a set of network services that provides interoperability between heterogeneous systems. The TCP portion is responsible for providing reliable and recoverable communications between two end points. The IP portion sets up the routing used by TCP to transmit.

TELCOS ¾ TELephone COmpanies

T1 ¾ a digital transmission method for multiplexing multiple voice and/or data channels over a system of copper wire cables with amplifiers or regenerators that reinforce the digital signal at intervals of about one mile. T1 offers a two-way connection at 1,544,000 bits per second. One T1 line carries a DS1 circuit, the equivalent of 24 port connections running at 64K bps. Depending upon the provisioning by the carrier, both leased channels and switched channels may be combined. Point-to-point dedicated T1 lines provide only permanent circuits. Switched T1 lines commonly use in-band signaling for call management, resulting in switched 56K bps channels.

UART (Universal Asynchronous Receiver/Transmitter) ¾ a device that performs asynchronous communication functions by converting parallel digital output from a DTE device into serial bit transmission and vice versa.

virtual circuit ¾ a communications link that appears to be a direct connection between sender and receiver, although the link can physically involve routing between a more circuitous path.

Wide-Area Network (WAN) ¾ a network composed of systems that are relatively far apart, meaning that the area is usually gauged in hundreds of miles. A WAN may also encompass a series of LANs connected over a wide area.

In this manual, WAN refers to a network consisting of lines provided by telephone companies.

wink start ¾ in placing a call, the T1 Modem Bank goes off-hook, then waits for a wink acknowledgment before dialing.

84 T1 Modem Bank