This publication provides guidance on the term "service animal" and the service animal provisions in the Department's regulations. Three templates for service dog letters from healthcare professionals, covering the types of letters service dog users may legally need.Sign your application and drop it in the mail to Working Dogs For Vets. Then give it a few days and give us a call at 843-647-4357. Over time, service dog functions expanded to assist people with various disabilities, including those who are deaf or hard of hearing. Hearing or Signal Dog is a dog that has been trained to alert a person with significant hearing loss or who is deaf when a sound, e.g. § 230-12.10 Entering into contracts with outside services. chevron_right. Our Service Dogs for Hearing are primarily black and yellow Labrador Retrievers. HSDC is one of the largest providers of ASL interpreters in the Puget Sound region. You can view a video announcing the merger here.