A PRA trunk is a digital circuit trunk and uses DSS1 signaling as the signaling control protocol. The trunk is divided into two sides, network side and user side.

Question

Options

• ATRUE
• BFALSE

• A
  81% (39)
• B
  19% (9)

Explanation

Option A is correct because a PRA (Primary Rate Access) trunk is indeed a digital circuit trunk that uses DSS1 (Digital Subscriber Signalling System No. 1) as its Layer 3 signaling protocol on the D-channel for call control. The PRA interface (also known as ISDN PRI) is inherently divided into a network side (the exchange/provider side) and a user side (the customer/PBX side), a distinction that governs how signaling messages are interpreted and which endpoint initiates certain procedures. Since this is a TRUE/FALSE question, option B is wrong simply because all three stated facts - digital trunk, DSS1 signaling, and the two-sided architecture - are accurate and well-established ISDN standards.

Memory tip: Think of "PRA = Primary Rate Access = Perfectly Right Answer" - it's a digital trunk (not analog), DSS1 is its signaling language, and like any telephone connection, there's always a network end (the provider) and a user end (your equipment).

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