Very great feature for a landline!!! Customer can text to the landline so you don't miss the business. This has been a game changer for my advertising firm. It helps me respond quicker to clients and provide better customer support to them. I have highly recommended this service to other colleagues.
Zipwhip - Zipwhip enables text messaging for landline, VoIP, and toll-free phone numbers.
WikiPro - All-in-one Business to Customer Communication
Heymarket - The professional way to text message. Your customers are mobile. Heymarket helps you manage those relationships from your smartphone.
Bandwidth - Bandwidth offers SIP trunking, Emergency communications, and Voice & Messaging APIs.
Respond Flow - The Mailchimp of SMS
Twilio - Brings voice and messaging to your web and mobile applications.