- A T1-transmission framing and
synchronization method, consisting of a series of digital 1's and 0's in a
unique order, one member of the series being sequentially inserted in a T1
stream after each 193 bits. See also B8ZS .
Data Communication Equipment (DCE)
- A configuration protocol which identifies Data Communication Equipment,
the type of data connection at equipment which connects to a
communications facility. Important when interconnecting RS-449, RS-232,
V.35, X.21 and other digital signals. Compare DTE .
Degradation Category Rating (DCR)
- Degradation Category Rating, an ITU-T P.800 subjective testing protocol,
similar to CCR but is based on the test subject always listening to the
reference signal, followed by the signal passed through the device under
test, a test performed by HEI.
Degradation Mean Opinion Score (DMOS)
- an ITU-T P.800 subjective listening test where the test subject compares
two signals, first the reference, then the signal passed through the
device under test, a test performed by HEI.
- The equipment used by end users to run or "play" an
- Also called Difference Frame. Contains only the pixels different from
the preceding Key Frame. Delta Frames reduce the overall size of the video
clip to be stored on disk. Also see Key
Differential Interframe Coding
- In motion video compression. The transmission of only the difference
information between adjacent video frames.
Digital Access Cross-connect System (DACS)
- Included as part of public and private digital networks, a DACS may
commonly switch DS3, DS1 and DS0 signals and is
useful for configuring complex networks. A DACS is not a substitute for an
- Captures images (still or motion) digitally and does not require
analog-to-digital conversion before the image can be transmitted or stored
in a computer. The analog-to-digital conversion process (which takes place
in CODECs) usually causes some
degradation of the image, and a time delay in transmission. Avoiding this
step theoretically provides a better, faster image at the receiving end.
Digital Imaging and Communications in Medicine (DICOM)
- A standard for interconnection of medical digital imaging devices,
developed by the ACR-NEMA
committee sponsored by the American College of Radiology and the National
ctrical Manufacturers Association. DICOM v.3.0 is a vendor-independent
standard for data formats and transfer that emphasizes point-to-point
connection. SEE ALSO RIS.
- coded in discrete numerical values (bits). Digital data streams are less
susceptible to interference than analog data streams. Also, because they
are made up of zeros and ones (bits) than can be manipulated and
integrated easily with other data streams (voice/video/data).
Direct Digital Imaging
- Involves the direct capture of digital images (e.g., an MRI)
so that they can be electronically transmitted. This is in contrast to an
x-ray that is first made into a film and then photographed for
digitization to send or store.
- Flat panel displays, cathode-ray tubes and related technologies which
emphasize cost-effective increases in screen size, resolution, and image
quality. Technologies include liquid crystal, electroluminescent, plasma
and vacuum fluorescent.
- The AT&T Bell System level 0 digital standard for systems operating
- The AT&T Bell System level 1 digital standard for systems operating
at 1.544 Mbps and consisting of 24 DS-0 channels.
- The AT&T Bell System level 3 digital standard for systems operating
at 44.736 (45) Mbps.
Dual Communications Interface
- An interface which allows simultaneous transmission of the two halves of
a set of communications data over two similar communications interfaces.
The most common application is for connection using two switched 56 Kbps
transmission circuits or an ISDN-BRI
- Full duplex describes the ability of both ends of a conference to speak
and be heard simultaneously (like a regular phone call). Half duplex audio
supports only one site speaking at a time; other speakers will be cut off.
- The ability of the consultant to "interview and examine" the
patient WITH the remote/deployed medical provider thru the use of scopes,
live video and still images.