Download End-user PTT services offered by PTTSystems Ltd.

Information
on the implementation of Push-to-Talk services
PTTSYSTEMS LTD
page 1
Table of contents
Foreword ................................................................................................................................................ 3
About our company .............................................................................................................................. 3
A general overview of the service ...................................................................................................... 4
Features ............................................................................................................................................. 4
Technical specifications ....................................................................................................................... 5
The solution of PTTSystems Ltd. ....................................................................................................... 6
End-user PTT services offered by PTTSystems Ltd. ...................................................................... 6
Upcoming end user services from PTTSystems Ltd. ...................................................................... 7
PTTSYSTEMS LTD
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Foreword
We are proud to present this information material about the implementation of Push-to-Talk
services for mobile phones. PTTSystems Ltd. is a registered digital telecommunication
service provider and IT systems integration enterprise. Our company aims to deliver highend cutting edge technologies to its clients. The main strategic objective of the company is
operate as a virtual provider and as such, to release valuable services like Push-to-Talk and
expand the operator’s portfolio with these value added services.
With the needs of our clients in mind, we provide a summary of the technological and
commercial requirements of our services.
About our company
What do PTTSystems and their partners have to offer?
As a member of the HAISystems group, PTTSystems Ltd. primarily operates on the
Hungarian IT market. Aside from IT services, we have started developing digital Push-to-Talk
services based on our substantial technical expertise. Currently, our company is the only one
in the Hungarian market that offers a competitively priced, digital alternative to walkie-talkies
that can be maintained inexpensively. Our highly qualified experts, quality products, wide
range of related services and experience in system solutions and integration ensure our
company’s reliability as a stable partner. Our clients are companies with a substantial history
and experience, being central players in the international, as well as the Hungarian market.
Background for our system integration services is provided by our team of experts; this
cooperation plays a crucial role during projects, from installation and implementation to
system tracking.
We hope to see you among our satisfied clients.
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A general overview of the service
Push-to-Talk (PTT) provides walkie-talkie-like functionality over a cellular network. The
service functions like CB or UHF radio transceivers, but using cellular phone networks and
mobile phones and transmitting voice in data packets, with all of the associated advantages.
With the proliferation of cellular phones, services utilizing CB or UHF transceivers have
expressed a need for a unified solution that can provide the functionality of both using a
single device, using the pre-existing cellular infrastructure and incurring no additional
frequency fees. There are existing solutions for emergency and disaster control services,
such as TETRA and TETRAPOL; however, these need completely new infrastructures,
resulting in costs that are significantly higher than our PTT system’s.
PTT services are aimed at clients who need a simple and inexpensive solution that can be
activated and used immediately.
Internet
Mobilszolgáltató II.
Mobilszolgáltató I.
PoC Szerver
Features

half-duplex transmission, with one user transmitting (speaking) at a time

communication can be private, with transmission (speech) between two users

transmission can be started without dialing

the PTT system supports group communication. A single user can be a member of
several groups, receiving and sending messages in all groups

no special device is required

communication using Push-to-Talk technology is not restricted by range

the service can be used in any cellular phone network which supports GPRS
(General Packet Radio System), EDGE (Enhanced Data rate for Gsm Evolution),
UMTS (Universal Mobile Telecommunication System) and HSDPA (High-Speed
Downlink Packet Access) technologies
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
the PTT service is IP-based, thus, it can be used independently of the cellular service
provider (e.g.: over a Wi-Fi network)
Technical specifications
The definition of the Push-to-Talk over Cellular (PTT) service was developed under the
auspices of the Open Mobile Alliance (http://www.openmobilealliance.org). The PTT system
provides half-duplex communication services, thus, no other users can access the network
while one of them is transmitting (speaking). The reasoning behind this method of
implementation was to avoid presenting a rival to mobile voice services and to provide a user
experience that is reminiscent of radio-based systems. Communication between PTT clients
and the server is IP protocol based. Clients can connect to the IP-based network directly or
through cellular services. Usage of the service through direct connection is independent of
cellular service providers. When connecting through cell phone networks, the client transmits
packets through the mobile phone service provider’s APN (Access Point Name). The APN
and PTT servers communicate using IP protocol. In this case, the type of data connection
between the cellular phone and the service provider depends on the services available in the
given network, the connection protocols supported by the client program and the service that
the user has subscribed to. Widely used mobile data transfer protocols include GPRS,
RDGE, UMTS and HSDPA.
802
.11x
802.1
1x
Vezetéknélküli hozzáférési pont
E
ED G
S
GPR
PoC APN
Internet
Mobilszolgáltató I.
PoC APN
EDGE
UMTS
Mobilszolgáltató II.
PoC Szerver
The application level control protocol used in the PTT system is SIP (Session Initiation
Protocol). SIP signaling is used in several VoIP (Voice over IP) systems. The real-time
PTTSYSTEMS LTD
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transfer of data, video and audio were the functions that SIP has been developed to fulfill.
Traditionally, it uses port 5060 of the TCP/UDP protocols.
The solution of PTTSystems Ltd.
Two factors are crucial in ensuring high-quality service: the quality of data transfer provided
by the cell phone network and the “best effort” mindset promoted by public IP-based
networking.
When using data services, cell phones connect to an APN through which they access further
services. Generally, each user connects to a default internet service APN. Users who
subscribe to data services can use this with the same conditions and equal access. Since an
APN’s throughput capacity is limited, users “compete” for this resource. Thus, in order to
maintain a constant quality of service, a separate APN is recommended for PTT.
Communication between APN and PTT servers is conducted through the publicly accessible
internet. Standard telephone services do not allow users to make calls when the network is
occupied. However, the internet allows every transfer through based on the “best effort”
principle. One of the methods to ensure quality in this system is connecting the PTT server to
the cell phone service provider through a Virtual Private Network (VPN).
E
ED G
S
GPR
Mobilszolgáltató I.
APN
APN
Internet
VPN
EDGE
UMTS
Mobilszolgáltató II.
VPN
PoC Szerver
PTT solutions can be accessed using Nokia cell phones using the Symbian OS or industrial
mobile phones based on OMA standards. Like every other installed application, the PTT
service decreases the standby time of the device.
End-user PTT services offered by PTTSystems Ltd.

Push-to-Talk functions can be switched on and off independently of telephone
functions
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
PTT messages are only received if the PTT client is running and logged on to the
given group

the handset displays the sender and the group of a message

any user can create groups and invite new members to them

the users connecting to groups can be monitored

a user can be a member of several groups

when being invited to a group, users can decide to accept or decline an invitation

private talks can also be initiated by selecting the user’s number from the phone book
or using the keyboard

users with no PTT service running cannot be invited to group or private talks

incoming and outgoing voice calls interrupt the data connection, thus the user does
not receive PTT messages and cannot transmit in the PTT system

the arrival of a message is not guaranteed if the device is transmitting or receiving
another PTT message
Upcoming end user services from PTTSystems Ltd.

support for PDAs running Windows Mobile 5 and 6, industrial-grade, dust, oil and
impact resistant Sonim devices and Windows CE based embedded systems, apart
from the currently existing Nokia solutions

administration and dispatch interface for the PC, enabling the easier management of
multi-user environments

GPS tracking systems for suitable devices
PTTSYSTEMS LTD
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