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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 page 2 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. PTTSYSTEMS LTD page 3 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 PTTSYSTEMS LTD page 4 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 page 5 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 PTTSYSTEMS LTD page 6 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 page 7