Digital circuit multiplication equipment (DCME) was a type of voice compression equipment that is installed at both ends of a long-distance telecommunication link, typically a link via

communications satellite A communications satellite is an artificial satellite that relays and amplifies radio telecommunication signals via a Transponder (satellite communications), transponder; it creates a communication channel between a source transmitter and a Rad ...

submarine communications cable A submarine communications cable is a cable laid on the seabed between land-based stations to carry telecommunication signals across stretches of ocean and sea. The first submarine communications cables were laid beginning in the 1850s and car ...

. The main characteristics of DCME are defined in ITU-T recommendation G.763. DCME consists of a

time-assignment speech interpolation In telecommunications, a time-assignment speech interpolation (TASI) was an analog technique used on certain long transmission links to increase voice transmission capacity. TASI was invented by Bell Labs in the early 1960s to increase the capaci ...

(TASI) voice interpolation stage, which is a form of

statistical multiplexor Statistical multiplexing is a type of digital communication link sharing, sometimes abbreviated as STDM. It is very similar to dynamic bandwidth allocation (DBA). In statistical multiplexing, a communication channel is divided into an arbitrary num ...

applied to voiceband signals, and a low rate encoding stage which exploits correlation between successive voiceband samples on an individual input channel to reduce the transmitted bitrate from that required by

PCM Pulse-code modulation (PCM) is a method used to Digital signal (signal processing), digitally represent analog signals. It is the standard form of digital audio in computers, compact discs, digital telephony and other digital audio application ...

of equivalent quality. Under heavy loading conditions, for example when a large number of channels show continuous activity due to voiceband data or Group III facsimile signals, the voice interpolation may not be able to operate within a satisfactory quality range – discontinuous signals such as speech being affected by competitive clipping of the initial part of the activity. To combat this DCME may incorporate Dynamic Load Control on a range of input channels. Dynamic load control is a form of back busying to the telephone switch. The DCME's functionality, from the point of view of the telephone switch attached to its local interface, is standardised by

ITU-T The International Telecommunication Union Telecommunication Standardization Sector (ITU-T) is one of the three Sectors (branches) of the International Telecommunication Union (ITU). It is responsible for coordinating Standardization, standards fo ...

Recommendation Q.50.

References

Multiplexing {{Telecomm-stub

See also

References