Multitech MTPSR1-202ST Podręcznik Użytkownika Pobierz pdf (Strona 93)

Glossary

MTPSR1-202ST

E&M: A telephony trunking system used for either switch-to-switch, or switch-to-network, or com-

puter/telephone system-to-switch connection.

EIA: The Electronics Industries Association is a trade organization in Washington, DC that sets

standard for use of its member companies. (See RS-232, RS-422, RS530.)

Encapsulation: A technique used by network-layer protocols in which a layer adds header informa-

tion to the protocol data unit from the preceding layer. Also used in “enveloping” one protocol inside

another for transmission. For example, IP inside IPX.

Errored Seconds (ES): Any second of operation that all 1.544M bits are not received exactly as

transmitted. Contrast “Error Free Seconds”.

Error Free Seconds (EFS): Any second of operation that all 1.544M bits are received exactly as

transmitted. Contrast “Errored Seconds”.

ESF Error Event: A T1 error condition that is logged when a CRC-6 error or an OOF error occurs.

Ethernet: A 10-megabit baseband local area network that allows multiple stations to access the

transmission medium at will without prior coordination, avoids contention by using carrier sense and

deference, and resolves contention by using collision detection and transmission. Ethernet uses

carrier sense multiple access with collision detection (CSMA/CD).

Excess Zeros: A T1 error condition that is logged when more than 15 consecutive 0s or less than

one 1 bit in 16 bits occurs.

Exchange: A unit (public or private) that can consist of one or more central offices established to

serve a specified area. An exchange typically has a single rate of charges (tariffs) that has previously

been approved by a regulatory group.

Exchange Area: A geographical area with a single uniform set of charges (tariffs), approved by a

regulatory group, for telephone services. Calls between any two points within an exchange area are

local calls. See also “Digital PBX”, “PBX”.

Exchange Termination (ET): The carrier’s local exchange switch. Contrast with “Loop Termination -

LT”.

Explicit Congestion Management: The method used in frame relay to notify the terminal equipment

that the network is overly busy. The use of FECN and BECN is called explicit congestion manage-

ment. Some end-to-end protocols use FECN or BECN, but usually not both options together. With

this method, a congestion condition is identified and fixed before it becomes critical. Contrast with

“implicit congestion”.

Extended Super Frame (ESF): One of two popular formats for framing bits on a T1 line. ESF

framing has a 24-frame super-frame, where robbed bit signaling is inserted in the LSB (bit 8 of the

DS-0 byte) of frames 6, 12, 18 and 24. ESF has more T1 error measurement capabilities than D4

framing. ESF and B8ZS are typically both offered to provide clear channel service.

Failed Seconds: A test parameter where the circuit is unavailable for one full second.

Failed Signal: A T1 test parameter logged when there are more than 9 SES (Severely Errored

Seconds).

Fax (facsimile): Refers to the bit-mapped rendition of a graphics-oriented document (fax) or to the

electronic transmission of the image over telephone lines (faxing). Fax transmission differs from data

transmission in that the former is a bit-mapped approximation of a graphical document and, therefore,

cannot be accurately interpreted according to any character code.

Firmware: A category of memory chips that hold their content without electrical power, they include

1 2 ... 88 89 90 91 92 93 94 95 96 97 98 ... 103 104

Komentarze do niniejszej Instrukcji

Brak uwag

Multitech MTPSR1-202ST Podręcznik Użytkownika Strona 93

Komentarze do niniejszej Instrukcji

Powiązane produkty i podręczniki dla Networking Multitech MTPSR1-202ST