D channel (Delta channel or Data channel)

In the integrated service digital network (ISDN), a

channel designated for out-of-band signaling and control functions. Standard ISDN interfaces include multiple B (Bearer) channels that carry user payload and a D channel for signaling and control. Basic rate interface (BRI) comprises two B channels at 64 kbps and one D channel at 16 kbps, and is often referred to as 2B+D. Primary rate interface (PRI) comprises 23 B channels at 64 kbps, plus a D channel at 64 kbps, is compatible with North American T1 and Japanese J-1 standards, and is often referred to as 23B+D. Primary rate access (PRA) comprises 30 B channels at 64 kbps, plus a D channel at 64 kbps, is compatible with European E-1 standards, and is often referred to as 30B+D. A D channel also can support low-speed end user packet data and telemetry applications. See also D, B channel, BRI, E-1, ISDN, J-1, packet, payload, PRA, PRI, and T1.

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• Section Overhead (SOH)
• section terminating equipment (STE)
• Secure European System for Applications in a Multivendor Environment (Sesame)
• Secure Hypertext Transport Protocol (S-HTTP)
• Secure Multipurpose Internet Mail Extension (S/MIME)
• Secure Sockets Layer (SSL)
• security
• security
• security
• security management
• seed rod
• segment
• segmentation
• segmentation and reassembly (SAR)
• seizure
• selective call acceptance
• selective call block
• selective call forwarding
• selective call rejection
• selective ringing
• selector
• selenium
• self-healing
• self-learning bridge
• semiconductor