(ANSI) Standard T1.618 and the International Telegraph and Telephone Consultative Committee (CCITT) Standard Q.922, indicates the functions associated with certain DLCI values:

DLCI ValuesFunction

 

 

0

In-channel signalling

 

 

1-15

Reserved

 

 

16-991

Assigned using frame-relay connection procedures

 

 

992-1007

Layer 2 management of frame-relay bearer service

 

 

1008-1022

Reserved

 

 

1023

In-channel layer management

 

 

DCD (Data Carrier Detect) ◆ See CD (Carrier Detect).

DCE (Data Communications Equipment, Data Circuit-Terminating Equipment) ◆ Equipment that provides the functions required to establish, maintain, and terminate a connection (including signal con- version) for communications between the data terminal equipment and the telephone line or data circuit. Also, interface signals typically presented by this equipment.

D Channel ◆ Standard channel on an ISDN PRI or BRI line. At 16 Kbps, a D channel carries all signalling information and can carry low- speed packet data such as X.25 packet switching.

DE ◆ See Discard Eligibility (DE).

Demarc (Demarcation Point) ◆ The point on a customer's premises where the line from the telephone company meets the customer's wiring at the customer's premises.

DFT ◆ See Distributed Function Terminal (DFT).

Directory Number ◆ Yourseven-digittelephonenumber(withoutthe area code), as found in the telephone directory. Each BRI connection can have up to two Directory Numbers, one for each B channel.

Discard Eligibility (DE) ◆ A bit indicating that a frame may be discarded in preference to other frames if congestion occurs to maintain the committed information rate. See also Excess Burst Size and CIR.

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