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GlossaryGlossaryGlossaryGlossary-8 August 2003 Access Navigator - Release 1.8
Glossary
E1 European CEPT digital signal level 1, similar to the North American DS1 except
that the E1 information rate is 2.048 Mbps and transports 30 DS0 signals,
compared to the 24 DS0 signals in the North American DS1. E1 also employs a
separate signaling channel instead of using robbed-bit signaling, so all 8 bits of the
DS0 are used to code the wave shape of the digitized voice sample.
Electronic
Business Set
(or Service)
See P-Phone.
Embedded
Operations
Channel
EOC. The GR-303 switch system communicates with the Access Navigator using
an EOC and Timeslot Management Channel (TMC) in the GR-303 Interface
Group (IG). The EOC carries management data (provisioning, messages, and
alarms), while the TMC carries call setup data. The switch sets up crossconnects
in the Access Navigator between switch DS0s and drop DS0s. Each drop DS0 is
identified by a unique Call Reference Value (CRV).
Extended
Superframe
ESF. A North American format for DS1 rate signals at 1.544 Mbps that extends
the capability of the Superframe (or D4) format to include a 4 Kbps facility data
link channel by using some of the 8 Kbps overhead used for synchronization.
Facility Data
Link
FDL. An out-of-band communications link used for traffic maintenance. The DS1
Extended Superframe (ESF) format provides an FDL channel with 4 Kbps data
rate.
Failure A termination of the ability of an item to perform a required function. A failure is
caused by the persistence of a defect.
Filling Consolidating traffic into one line, such as a DS1, for more efficient transport.
Foreign
Exchange
FX. A telephone service providing local access to a central office that is outside
of (foreign to) the subscriber's local exchange area. A Foreign Exchange Office
(FXO) provides dial tone to a Foreign Exchange Station (FXS).
Fractional
Interface
A service interface using only a portion of the available capacity. In the Access
Navigator, this term refers to a DS1 or T1 connection using fewer than 24 DS0s.
The fractional interface is a group of sequential DS0s in the same DS1, such as
DS0s 19 through 24.
Framing An error control format used to multiplex digital data, such as DS0 channels, into
larger frames, such as DS1 (T1) and DS3. Frames contain time slots for each
channel’s data and include a framing bit to synchronize the receiver so it can de-
multiplex the data and recover the individual channels. The most common
framing for DS1 transport are D4, S4, and ESF.
Frequency The number of cycles of periodic activity that occur in a discrete amount of time.
Gateway Any device that passes packets from one network to another network in their trip
across the Internet. A gateway usually has its own network IP address.