Which statement accurately describes ISDN Primary Rate Interface (PRI)?

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Multiple Choice

Which statement accurately describes ISDN Primary Rate Interface (PRI)?

ISDN PRI on a North American T1 line uses 23 bearer (B) channels for user traffic and a single signaling (D) channel. Each B channel is 64 kbps, so the 23 B channels provide 1,472 kbps for user data. The D channel runs at 64 kbps and carries call setup, teardown, and signaling information. Together they fit into the T1 rate of 1.544 Mbps, with 1.472 Mbps of user data and 64 kbps of signaling. This matches the description of 23 × 64 kbps channels plus one 64 kbps signaling channel, which is the correct PRI configuration for this context. The other options are inconsistent: there isn’t a 64 kbps data channel separate from signaling in PRI, there isn’t a 128k-channel PRI on T1, and signaling relationships don’t determine higher cost simply by using fewer channels. (Note that Europe uses a different arrangement: 30 B channels plus a 64 kbps D channel on an E1.)

ISDN PRI on a North American T1 line uses 23 bearer (B) channels for user traffic and a single signaling (D) channel. Each B channel is 64 kbps, so the 23 B channels provide 1,472 kbps for user data. The D channel runs at 64 kbps and carries call setup, teardown, and signaling information. Together they fit into the T1 rate of 1.544 Mbps, with 1.472 Mbps of user data and 64 kbps of signaling.

This matches the description of 23 × 64 kbps channels plus one 64 kbps signaling channel, which is the correct PRI configuration for this context. The other options are inconsistent: there isn’t a 64 kbps data channel separate from signaling in PRI, there isn’t a 128k-channel PRI on T1, and signaling relationships don’t determine higher cost simply by using fewer channels. (Note that Europe uses a different arrangement: 30 B channels plus a 64 kbps D channel on an E1.)

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