|Photo credit: Ultratec
Based on a contribution by
co-Convener of the Joint Coordination
Activity on Accessibility and Human
How do you make a phone call if you are
deaf? Or, more to the point, how do you
respond to a call? Do you have to ask your
child or your neighbour to make appointments
for you or provide personal details to
a caller? Do you have to run out into the street looking for someone
to call an emergency service? These are just some of the scenarios
that a hearing person takes for granted will not happen.
There are many different types of deafness: profoundly deaf
people who use only sign language; profoundly deaf people who
have intelligible speech; profoundly deaf people who have less
intelligible speech; hearing people who are deafened; people
who are blind as well as deaf; and people who are hard of hearing.
People with age-related disabilities may fall into any of these
Many deaf people have problems in daily living by not being
able to make telephone calls to hearing people or organizations
without someone or something in place to assist them. This is
why relay services are so important for deaf telecommunication.
They are professional services that do not rely on the kindness of
friends, family or strangers.
But while relay services have been
around for more than 40 years, most countries
still do not offer these services for deaf
people, even though hearing impairment is
reportedly the most frequent sensory deficit
in human populations, affecting an estimated
250 million people in the world.
Today, being able to make contact by
telephone is a prerequisite for effective participation
in society. And the United Nations
Convention on the Rights of Persons with
Disabilities provides for “Full and effective
participation and inclusion in society”.
From teleprinters to videophones and more
In the 1960s, deaf people started using teleprinters (teletypewriters,
also known as TTY) with custom made acoustically
coupled modems to communicate with each other over the telephone
network. The modems used the ordinary telephone handset
as the transmitting device, thus enabling text to be sent over
the telephone network, character by character. This was in real
time and was the first real-time text later standardized at ITU
as part of Total Conversation and used in the first accessibility
standard (ITU–T V.18) for text phones.
Teletypewriters led to the development of text telephones,
which incorporated the printing device and the modem in one
When deaf people need to communicate
with hearing people who
do not have text telephones, there is
a problem. Based on the work of the
early pioneers (see article How the deaf developed a phone of their own), who
were all deaf, the response has been to
develop a relay service.
As technology progressed and the
Internet developed, it became possible
for deaf people to communicate with
each other using video. This works for
deaf people who use sign language.
Many deaf people who have sign language
as their first language find it difficult to use text phones because they
require written language. Videophones
have become increasingly popular
with these deaf users. They use them
to communicate with each other, and
with hearing people who can use sign
What is a relay service?
|Photo credit: BT
|Video phones and text phones are
among devices that benefit from ITU’s standardization work
A relay service is simply a way of enabling a deaf person —
using whatever modality they choose — to communicate with a
hearing person, and vice versa (Figure 1).
The modality used by the deaf caller may be text, voice or
sign. The different types of relay services meet the different individual
needs. These different types of relay services for deaf
people are: text relay service; text relay service with voice carry
over; captioned telephone relay service; and video relay service.
Text relay service
In a traditional text telephone relay service (Figure 2), deaf
callers use a bespoke text telephone terminal to type the words
that they want to say. A more modern version uses the Internet,
and is known as an Internet Protocol (IP) relay service. This can
be accessed via a personal computer, laptop, personal digital assistant
or smartphone. Both use the same operating method:
The deaf caller types his or her communication to a text relay
service centre, where a relay operator will read aloud the
typed words to the hearing caller.
The hearing caller speaks to the relay operator, who will transcribe
the speech as text, transmitting the typing back to the
deaf person’s terminal, whether this is a text telephone or an
Internet device such as a laptop or a smartphone.
Text relay service with voice carry over
For a deaf person who has speech that can be understood
by the hearing caller, the deaf person can use a variant of a
telephone relay service known as voice carry over (Figure 3).
Instead of typing the words, the deaf person speaks directly to
the hearing caller. The hearing caller speaks to the relay operator,
who will transcribe the words as text, which goes back to the
deaf person’s display screen. The flow is either voice or text, but
not both at the same time.
Text relay services are available in many countries, including
the United States, Canada, Australia, New Zealand, the United
Kingdom, Sweden and Denmark.
Captioned telephone relay service
A captioned telephone relay service (Figure 4) is the most
functionally equivalent and appropriate type of relay service for
people who are hard of hearing, people who have been deafened,
and deaf people whose speech can be understood by hearing
people. This is an enhanced voice carry over system where a
deaf person has a normal telephone conversation in both directions
with the hearing caller.
The hearing person’s speech path is split into two: one
path goes directly to the deaf caller, who may understand most,
some or none of the speech, depending on their level of hearing
loss or the level of background noise. The other path goes to
a captioned telephone relay service centre, where a captioning
assistant will revoice everything the hearing person says, word
for word, into a voice recognition engine. The transcribed text is
transmitted to the deaf user’s display, which could be a laptop
or a smartphone.
A captioned telephone relay service can be accessed through
the Internet using any browser device, such as a personal computer,
laptop, netbook, tablet, personal digital assistant or
Captioned telephone relay services are available in the
United States every hour of the day and night, every day of the
year. The cost to the user is the same as the cost of a standard
telephone call. Australia is trialling a captioned telephone relay
service, and New Zealand has issued a tender for one.
Many people with age-related disabilities cannot cope with
computers; a bespoke captioned telephone is what they need.
This looks like a normal telephone but with a large display to enable
them to see transcribed text from the hearing caller.
Video relay service
A video relay service (Figure 5) is used by deaf people whose
first language is sign language. Many of these people do not
have sufficient written language skills to use text relay services.
And they do not have sufficiently intelligible speech to use a captioned
telephone relay service. They use either videophones or
a webcam on their personal computer, laptop, tablet or smartphone
(with the webcam in front), together with videophone
software or apps. They sign their concepts to a video relay centre,
where a sign language interpreter will translate from their sign
language concepts into spoken language, then voice over to the
hearing caller. The hearing caller speaks to the sign-language
interpreter who translates this into sign language for the deaf
Funding of relay services
Because a human interface is needed between the deaf
and hearing callers, relay services have to be funded. These human
interfaces might be text relay service operators, captioned
telephone relay service captioning assistants, or video relay service
How can these services be funded? Each country has different
ways of funding the services. In some countries, relay services
are funded by government (as in Sweden), in others they are
funded either by the telecommunications industry (for example,
in the United States) or as part of universal service (as in the
Costs in the United Kingdom
The text relay service in the United Kingdom is more than
27 years old and uses old technology. The service is currently
under review, and a potential provider of services commissioned
research on the economic benefits of a video relay service for
deaf sign-language users. According to the results of the research,
over a period of 10 years, providing a video relay service
will cost between GBP 734 million and GBP 851 million, while
the economic benefits to society will amount to between GBP
996 million and GBP 1.1 billion.
Relay services do cost money, but the real benefits to society
outweigh these costs. Providing relay services will result in
increased employability and improved health benefits for deaf
people, and their better integration into society.
Deaf children in developing countries
Imagine a rural village in Africa where a deaf child is born
to hearing parents. The parents would need access to information
about how to develop the language ability of their child.
Without such information, the deaf child might remain isolated
from everyone in the village, because no one would be able to
communicate with him or her.
The power of telecommunications could break this mould.
Mobile Internet and solar-powered Internet devices would offer
the parents of the deaf child enhanced access to information. Most
importantly, the deaf child could take part in social interaction via
video telephony, which could lead to better language and literacy
development. This would enable deaf children to use future relay
services, and would thus improve their lives through social integration,
improved employability and better career prospects.
ITU’s Telecommunication Development Sector (ITU–D) could
work with the United Nations Children’s Fund (UNICEF) to undertake
an experimental project to provide relay services for deaf
children in developing countries. This would be a powerful way
of enhancing these deaf children’s lives.
The technology of relay services has been established for
many years. Now countries need to consider setting up relay
services, where such services do not already exist. The work of
ITU’s Telecommunication Standardization Sector (ITU–T) on relay
service standards is of paramount importance. It is crucial to ensure
that all deaf people are able to communicate with anyone
everywhere, just like their hearing peers.
About Christopher Jones
In the early 1970s, Christopher Jones, who is profoundly deaf, set up a local relay service using 24 teleprinters, having
raised funds by making and selling soft toys. The teleprinters, precursors to text telephones, enabled local deaf
people in the United Kingdom to communicate across the telephone network for the first time in their lives. Within a
couple of years, this led to the development of the United Kingdom’s second local text telephone relay service, many
years before the establishment of a national text telephone relay service. Since 2007, Christopher Jones has been
Director of AccEquE Ltd, a consulting company engaged in promoting enhanced accessibility and equality in electronic
communications for deaf, deafened, deaf blind and hard-of-hearing people.