1. AT&T Unlimited Premium PL offer for AT&T Signature Program members: Requires proof of eligibility. Credit(s) will show within 2 bill periods. A $10-per-month discount applies per phone line, but only to phone lines 1 to 5. Any additional phone lines added over 5 and up to a maximum of 10 reduces all phone-line (including lines 1 to 5) discounts to $5 per month per phone line. Eligibility requirements and other restrictions apply.