It is possible to set timers on Auto-Attendants, the options are 'Timeout before first key press', 'Timeout after last key press', and 'Maximum key presses to collect'. Clicking 'Set Custom' will reveal a sliding bar with 1-10 as options (in seconds).

The sliders do not show the system default times when initially enabled.

Timeout before first key press

'Timeout before first key press' is the amount of time a caller will have to enter a digit before the 'if no key is pressed' option is followed.

The system default for timeout before first key press is 4 seconds.

Timeout after last key press

'Timeout after last key press' is the amount of time a caller will have to finish their key presses. The timer starts over after each DTMF keypress.

The system default for timeout after last key press is 3 seconds.

Maximum key presses to collect

'Maximum key presses to collect' limits the amount of DTMF to be collected before the 'Timeout after last key press' is engaged. If the maximum key press is set to 3, and the caller enters 3 digits, it will immediately proceed to the destination.