WAN Terms and Acronyms
DSX-1 — Short-haul version of DS1(coaxial cable being used as the media defines it as short-haul) by definition, coaxial cable is short-haul.
DSX-3 — Short-haul version of DS3 (coaxial cable being used as the media defines it as short-haul) by definition, coaxial cable is short-haul.
DTE — Data Terminal Equipment, equipment that originates and terminates data transmission such as a computer or printer (see DCE).
E-1 — European digital signal level 1. Similar to T1 but provides 32 channels (2.048 Mbps) instead of 24 channels (1.544 Mbps).
ESF — Extended Super Frame. A new T1 framing standard (see D4 framing) that uses 24 T1 frames, thus allowing individual identification of the channel and signaling bits.
EXZ — Excessive Zeros, an EXZ is the occurrence of any zero string length equal to or greater than 3 for B3ZS, or greater than 4 for HDB3.
Fractional T1 — Use of a portion (less than the full 24 channels) of a T1 line.
Frame Relay — A network protocol that allows for many point-to-point virtual connections over a single access channel.
HDB3 — High Density Bipolar 3, used with E-1, a bipolar coding method that does not allow more than 3 consecutive zeros.
HDLC — High-Level Data Link Control, layer 2 (link layer) full-duplex protocol derived from SDLC.
INV. HDLC — A form of zero suppression in which all zeros in the HDLC packet are changed to ones and all ones are changed to zeros.
ISDN — Integrated Services Digital Network. Allows point-to-point connections at 64 Kbps or 128 Kbps when necessary and disconnects the line when not in use. With this service the user only pays for the time connected.
JBZS — Jam Bit-Zero Suppression, a form of zero suppression that places a one in the seventh bit of a timeslot. Reduces the effective throughput to 56 Kbps.
