This parameter sets the maximum number of times the unit will attempt to redial the remote end (0–60 attempts) if it encounters a busy or reorder signal during dial backup activation. You adjust this to balance between persistence and cost—higher counts mean more retry attempts, which increases phone charges but improves the chance of successful backup establishment. Setting it to 3 means the unit tries up to 3 times before giving up; setting it to 0 disables retries.