V.24 -- The CCITT
Interface standard for interchange circuits between data terminal
and data circuit terminating equipment (DCE).
Defines both Asynchronous and Synchronous operation. Combining
will be very similar to RS-232
-- The CCITT standard for voltage level
The CCITT Interface standard for synchronous high speed data
communications as defined by the
standard. Normally used for data transmission with circuits 56Kbps and
above. V.35 specifies a 34-pin connector and can transmit at speeds into
the millions of bits per second.- (Mbps)
VDSL (Very high data rate
Digital Subscriber Line) -- A higher
speed extension of
ADSL capable of much higher
data rates than ADSL
but over shorter lines. While no general standards exist yet for VDSL
<at the time of this print>, discussion has centered around the
following downstream speeds:
Upstream rates fall within a suggested range
from 1.6 Mbps to 2.3 Mbps. VDSL Downstream speeds are in
discussions of speeds from 13mbps to 55mbps (depending on distance). The principal reason T1E1.4 decided against "VADSL"
was the implication that VDSL would never be symmetric, when some
providers and suppliers hope for fully symmetric VDSL someday,
recognizing that line length will be compromised. Note: VDSL had been
called "VASDL" or "BDSL" or even "ADSL"
prior to June, 1995, when T1E1.4 chose "VDSL" as the official title.
VOD (Video On Demand)
- A service offered by video services which allow the customer to
petition delivery of a video move via real time, possibly at any time
the customer desires. This means the data transfer medium must
accommodate very high speeds. An arguable speed for smooth video is in
the 2.5Mbps (and up) range depending upon compression methods used.
VPN (Virtual Private Network)
-- A private data network that uses a
public data network to carry all traffic. Example: The Internet is a
type of VPN.