Which of the following network access standards is used to connect a station…

Concept

A network access recommendation identifies the boundary and service it standardizes: user equipment to network, packet assembly/disassembly, a general DTE-DCE interface, or inter-network signalling.

For packet-mode access, the defining scope is the DTE-DCE interface that carries packets between a terminal and a public data network.

Application

The stem asks for the standard used to connect a station to a packet-switched network. X.25 defines the interface between DTE and DCE for terminals operating in packet mode on public data networks.

Contrast

• X.3 specifies a Packet Assembly/Disassembly facility (PAD) in a public data network.

• X.21 specifies the DTE-DCE interface for synchronous operation on public data networks.

• X.25 specifies packet-mode DTE-DCE access to public data networks.

• X.75 specifies packet-switched signalling between public networks.

Cross-check

The boundary test confirms the result: station-to-network packet-mode access selects X.25, whereas network-to-network signalling would select X.75.

Result

Therefore, the required standard is X.25.