1. Enhancing Text Conversations With
Real-Time Text Technology
Jon Azpiroz, Elisa Martín Caro
María Fernanda Cabrera, Silvia de los Ríos
Karel Van Isacker
AEGIS Workshop and International Conference, Brussels

2. The background
● Voice communication
● Not possible for everyone
● Alternative manners (in the past ICQ,
now AOL IM)
● But what about mobiles?
● Quest for alternatives to traditional
voice telephony that could be accessible
across desktop and mobile
communications devices.
AEGIS Workshop and International Conference, Brussels

3. Background Of Text Communications
● TTY
● the device for the deaf (TDD) or
teletypewriter (TTY) (1964) (also used for
people with speech impairments)
● Problem: different textphone standards, need
for landline
AEGIS Workshop and International Conference, Brussels

4. Background Of Text Communications
● SMS
● Advantages
– Used by the hearing impaired community.
– Text-based, easy to use, affordable and mobile.
– Vibrating function of the handset alerts the user
about a message.
● Disadvantages
– Unreliable system
– Transmission delays
– Cost of the messages
AEGIS Workshop and International Conference, Brussels

5. Increase interactivity
● Instant Messaging (IM) for mobile devices
● More interactivity as users can exchange
messages faster and more efficiently.
● IM Messages are cheaper than SMS.
● Problem: lack of standardisation (BlackBerry,
MSN, Google, AOL, Yahoo, ICQ, FaceBook,
WhatsApp,…)
– Few IM clients work with different networks (Pidgin
for Win, InstantBird for Linux)
● Users cannot interrupt each other
AEGIS Workshop and International Conference, Brussels

6. Real-time Text
● Real-time text (RTT) is conversational
text that is sent and received on a
character by character basis.
● A more natural, bi-directional flow of
conversation takes place.
● Pioneered by ICQ in 1996.
AEGIS Workshop and International Conference, Brussels

7. RTT protocol status
● Usage of call control protocols for RTT
communications
100
92,3
90
80
70
60
50
40
30,8
30
20
10 7,7
0
SIP H.323 Unknown
AEGIS Workshop and International Conference, Brussels

8. RTT protocol status
● Usage of transport protocols for RTT
communications
90
84,6
80
70
60
50
40
30
20
15,4
10
0
ToIP Unknown
AEGIS Workshop and International Conference, Brussels

9. RTT protocol status
● Usage of presentation protocols for RTT
communications
100
92,3
90
80
70
60
50
40
30
20
10 7,7
0
T.140 Unknown
AEGIS Workshop and International Conference, Brussels

10. RTT Protocol Status
ToIP
T.140
RFC4103
RTP
UDP
IP
AEGIS Workshop and International Conference, Brussels

11. Are there any restrictions?
● Network Address Translators (NAT)
SIP headers SIP headers
SIP Priv. IP 192.168.1.2
SIP Priv. IP 192.168.1.2
Private IP address
NAT Public IP address
IP 192.168.1.2
IP 80.57.12.68
● May provide non-routable contact information
● Solutions:
● Server side: STUN / TURN servers to obtain
public IP address
● Client side: SIP ALG to remove private addresses
AEGIS Workshop and International Conference, Brussels

12. Are there any restrictions?
● Firewalls
Port 5060 + media Port 5060 + media
SIP comm. ports X SIP comm. ports
FW
HTML Port 80 HTML Port 80
● May block SIP port (5060) or media communication
ports
● Solutions:
● Client and/or server side: tunneling
● Client side: SIP ALG to communicate with the
firewall to open ports
AEGIS Workshop and International Conference, Brussels

13. Real-time Text brought to the mobile
● Based on J2ME
● wide availability of the application is one
of the most important requirements.
● Roughly 78% of the mobile phones sold
in 2010 were inexpensive feature
phones that run the Java Micro Edition
(Java ME) environment.
● Application will be compatible in mobile
devices with different OS such as
Symbian or BlackBerry.
AEGIS Workshop and International Conference, Brussels

14. Real-time Text brought to the mobile
● Functionality
● User should login with a
user name and password to
start using the applications.
● Once registered, the
application provides three
main functionalities: make /
receive real-time text calls,
see the call logs and
manage the RTT contacts.
AEGIS Workshop and International Conference, Brussels

15. Real-time Text brought to the mobile
● Functionality
● Select existing contact or type directly
the RTT address of the other user.
AEGIS Workshop and International Conference, Brussels

16. Real-time Text brought to the mobile
● Functionality
● Once the call is
accepted by the other
user
– 2 text boxes appear
– upper one show what
the remote user is
typing
– lower box shows what
user of device is
typing.
AEGIS Workshop and International Conference, Brussels

17. Real-time Text brought to the mobile
● User testing
● Spain, Belgium, Sweden, and the United
Kingdom
● 26 users with hearing impairments
● 11 experts and 11 tutors
● Feedback overall positive, and desire to
have this functionality directly
embedded in IM they use now
● But: 2 window conversation is new
AEGIS Workshop and International Conference, Brussels

18. Real-time Text brought to the mobile
● Next version (by August 2012)
● Chat based user interface (both
conversations shown in same screen).
● New modalities of communication.
● Character-by-character, versus word-by-
word.
● New client will be developed for LWUIT
Java devices. This will make RTT
compatible with touch screen devices.
AEGIS Workshop and International Conference, Brussels