For PRA trunk interconnection, timeslot 16 functions as a ().

Question

Options

• AMedia channel
• BSignaling channel
• CClock channel
• DVoice channel

• A
  11% (2)
• B
  5% (1)
• C
  68% (13)
• D
  16% (3)

Explanation

In PRA (Primary Rate Access) trunk interconnection based on the E1/PCM-30 frame structure, timeslot 16 (TS16) is specifically designated to carry clock synchronization information between interconnected exchanges, ensuring both ends maintain frame-level timing alignment. Without this dedicated clock channel, the receiving end cannot reliably demultiplex the 30 bearer channels from the bitstream.

Why the distractors are wrong:

• A (Media channel): Media traffic occupies timeslots 1–15 and 17–31 - these 30 slots carry the actual payload (audio/data).
• B (Signaling channel): While timeslot 16 is sometimes associated with CAS signaling in basic E1, in the PRA interconnection context examined here, the signaling function is handled by a dedicated D-channel arrangement, not TS16.
• D (Voice channel): Voice is a subset of media; voice channels are distributed across the 30 bearer timeslots, not TS16.

Memory tip: Think of TS16 as the "tick-tock" slot - the number 16 sits right in the middle of the 32-slot E1 frame, acting like a metronome that keeps both sides of the trunk perfectly in sync.

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