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 Speech-to-Speech Relay Service (STS)

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What is STS?
Who can use STS?
How to personalize your STS calls.
Want more information about STS?
DDTP first in Nation to provide Visually Assisted Speech-to-Speech (VA STS).


What is STS? 

The California STS service enables people whose speech is difficult for others to understand to communicate by telephone. With this service, you can make calls by yourself independent of the availability of your assistant or care taker. When you make a call using STS a specially-trained STS Communications Assistant (CA) will be on the line with you to assist you during your call. The CA can repeat what you are saying for the person on the other end. You and the person on the phone with you can decide how much of your speech will be repeated: only particularly difficult words or every word you say. No special equipment is needed. You may use your own voice or a Speech Generating Device (SGD). People can also make a call to you through the STS Relay Service. There is no charge to use this STS service; you pay only for the cost of the call from your phone service provider, if any. The California STS service is part of the California Relay Service (CRS), a program of the California Public Utilities Commission (CPUC).


Have any questions about STS? Contact the STS Training Line at the bottom of the page.


Who can use STS?

The STS service can be used by anyone whose speech is difficult for others to understand on the phone and would like to have assistance during their call. This service may be especially beneficial for people who have had a stroke, a laryngectomy, who  stutter, have Parkinson’s disease, Lou Gehrig’s, Multiple Sclerosis, Cerebral Palsy, brain injury, or any other condition that causes others to have difficulty understanding the user’s speech on the phone. People can also make a call to you through the STS service, e.g., family members, friends, medical professionals or businesses.

How to personalize your STS calls.

Let the CRS relay providers know in advance how you want your STS call handled – by 711 Choice or by a Customer Profile:

By registering your 711 Choice you can pre-select from the following options: 

  • Choice of CRS provider – AT&T or Hamilton; or no preferred provider
  • Type of Communication – Speech-to-Speech
  • Preferred Language – English or Spanish

After registering your choices, all your calls will be routed automatically to your chosen provider, a trained STS CA and in your preferred language. All providers will have this information.

You can also let the CRS Providers know exactly how you want your calls handled by setting up a Customer Profile. That includes, but is not limited to 

  • Conversation related information (e.g. a customized explanation of STS service to be provided to the persons you call, or a standard message from you that can be left on answering machines)
  • Call setup related information (e.g. your preferred long distance provider; a list of most frequently called names and numbers; when and where you can be reached if someone tries to contact you through STS relay)

In the Customer Profile, the choices you make are for your specified provider. If you would like to use your preferences with more than one provider, you will need to set up profiles with each of them. Even if you don’t have a Customer Profile, you can give the CA instructions before (s)he places your call. For example:

  • You can ask the STS CA to re-voice everything you say, or to only re-voice when the person you are talking to doesn’t understand, or not to re-voice anything unless you ask for assistance.
  • Before the actual call is placed, you can dictate a message to the CA to be used during the conversation.
  • You can ask the CA to retain parts or all of a message for use in future phone calls.


To set up or change a 711 Choice or Customer Profile, please contact the relay providers’ Customer Service: 



Customer Service
  English Customer Service  Spanish Customer Service 
Hamilton Relay  1-877-632-9095     1-877-419-8440
AT&T Relay  1-866-288-1909 1-866-288-4151



 Want more information about STS?

Both California Relay Service (CRS) providers, AT&T Relay and Hamilton Relay, have extensive Speech-to-Speech information and training materials on their Web sites.

Want to find out more about how a STS call works? How exactly can a STS CA assist you? What are your options to personalize your STS call? Visit the relay providers’ Web sites:

Hamilton Relay: Hamilton Relay 

AT&T Relay: AT&T Relay 

You can also download and/or request printed materials from CRS:

To receive a print copy, please call 1-866-409-0178 and provide your name, address, and which documents you would like to receive.

You can also contact the STS Training Line to discuss your questions with a live operator. Call Customer Service of either provider (below) and request the STS Training Line.


AT&T Relay (available in English Mon – Fri, 9am – 5pm, or by appointment): 1-866-934-4288 


Hamilton Relay (available 24/7): 1-877-632-9095 (English), 1-877-419-8440 (Spanish) 








DDTP first in Nation to provide Visually Assisted Speech-to-Speech (VA STS)

CRS is offering a new service that can enhance the relay experience of individuals with a speech disability: Visually Assisted Speech-to-Speech (VA STS).

For more information visit our VA STS page