A cordless telephone that uses separate radio frequencies for transmission from the base to the handset and from the handset back to the base is operating in which mode?

Introduction / Context:
Telephony requires two-way communication. Two common approaches are duplex (simultaneous talk and listen) and half-duplex (talk or listen at a time). Cordless systems often implement frequency-division duplex (FDD) with distinct uplink and downlink frequencies.

Given Data / Assumptions:

• Base and handset transmit on separate frequencies.
• No time alternation is described, implying simultaneous paths are possible.

Concept / Approach:

If two distinct frequencies are used concurrently—one for base-to-handset and another for handset-to-base—the system is frequency-division duplex (FDD), i.e., duplex operation. Half-duplex would share a single channel over time (time-division), not separate frequencies simultaneously.

Step-by-Step Solution:

Verification / Alternative check:

Consumer cordless standards (e.g., early analog cordless phones) commonly used paired channels (uplink/downlink) to allow full-duplex conversation.

Why Other Options Are Wrong:

• Half-duplex: not simultaneous; usually one channel shared in time.
• Either/neither: contradicts the clear FDD description.
• Simplex: one-way only, inapplicable to telephony.

Common Pitfalls:

Confusing duplex (simultaneous two-way) with half-duplex (alternating one-way) or assuming time-division when frequency-division is stated.

Final Answer:

Duplex arrangement (simultaneous two-way using different frequencies)