What type of telephone construction is more likely to be affected by polarity reversal issues?

The type of telephone construction that is more likely to be affected by polarity reversal issues is older touch-tone phones. These phones use a system of Dual-Tone Multi-Frequency (DTMF) signaling, where specific frequency pairs are transmitted when the buttons are pressed.

Polarity reversal can impact devices that depend on a specific voltage polarity to function correctly. Older touch-tone phones often utilized a simple design where reversing the polarity of the line could disrupt the circuit's ability to detect and interpret the DTMF signals correctly. In contrast, more modern digital and wireless phones have integrated circuits that are typically designed to be unaffected by polarity reversals, making them more robust in such conditions.

Analog phones also generally have some degree of tolerance to polarity changes, as they operate on a more straightforward principle of current flow rather than relying on precise frequency detection. Therefore, older touch-tone phones represent the clearest instance of a telephone type that will experience issues due to polarity reversal.