Ascom IP DECT

Digital Enhanced Cordless Telecommunication (DECT) standard provides general radio access technology for wireless telecommunication[68]. DECT is designed to provide any telecommunication network a variety of applications and services. A DECT system consists of a DECT fixed part, one or more base stations, and one or more DECT portable devices.

There is no restriction on how many base stations each network can include. Each DECT system supports traffic for up to 100000 users [68]. This technology is used all over world and is a worldwide standard within telecommunication[69]. Ascom IP DECT is a DECT system connected through an IP backbone within the Ascom UNITE system.

The Ascom UNITE system

Ascom UNITE system is build up by modules connected over an IP backbone. All the available modules are tightly integrated and exchange data using the proprietary UNITE protocol using TCP/IP. Each module runs on an hardware platform called ELISE (Embedded Linux Server) and comprises: a host router which handles all the internal communications and between the modules, a UNITE Name Server used to translate call IDs into internal addresses, a Web Server for module configuration, a Linux based operating system and a Host Attendant which handles the basic configuration and supervision of the installed software. All modules communicate as one system by using the UNITE protocol as a common platform. The main functionalities of the system include:

x Remote management;

x Number planning and advanced message routing;

x Group handling;

x System supervision and advance fault handling;

x Activity logger;

x User administration.

Ascom Enhanced System Services (ESS)

The ESS is the central unit of the UNITE system. It is based on ELISE hardware to manage portable devices and provide different services:

x Number planning and message routing;

x System supervision, logging and fault handling;

x Message routing based on alarm functionalities.

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It can be connected to different carriers: System 900, DECT and VoWiFi systems, and manages the number planning, the creation of user groups and configuration of individual users. The ESS is replaced by the context-aware system, CallMeSmart, and the PBX in order to override the standard call management.

Ascom Integrated Message Server (IMS)

The IMS is a middleware between the IP-DECT base stations and all the other modules within the Ascom UNITE system. It manages data directed to and from the phones, and supports the following services:

x Message distribution;

x Central phonebook;

x IMS messaging tool.

Ascom Open Java Server (OJS)

The OJS is part of the Ascom IP messaging platform. It is a programming server, which makes it possible to implement customized features not covered by the standard Ascom UNITE System, and it is directly interfaced with the IMS. Using OJS it is possible to make a Java application communicate with the Ascom messaging system, and also establish

communication with external systems like CallMeSmart. The communication between OJS and IMS is illustrated in Figure 3-1 and the communication with external systems is

illustrated in Figure 3-2.

Figure 3-1: OJS communication with the IMS [28]

Figure 3-2: OJS communicating with external systems [28]

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The OJS provides a Java interface called the Open Access Java server (OAJ). The OAJ is an API containing specific libraries that can be used to manage all the information listed in Figure 3-1 and it includes an application development kit, used for development of customer specific applications.

Ascom IP-DECT Base Station

The Ascom IP-DECT base station, shown in Figure 3-3, uses the DECT standard to enable full access to messaging and voice functions between the base station and the wireless handsets. It works as a bridge for data exchange between the Ascom wireless phones and the Ascom UNITE network. Its main characteristics are the following:

x DECT GAP/CAP radio interface;

x Supports H.323 or SIP protocol over IP;

x On-air synchronization;

x Web interface for configuration and software upgrade;

x Roaming and handover.

Figure 3-3: Ascom IP-DECT base station

Ascom handsets

We had two different types of handsets from Ascom available in the Context lab: 9d24 MkII and d62, shown in Figure 3-4 and Figure 3-5. The d62 differs from the 9d24 MKII by being more intuitive and with a coloured display not available on the 9d24 MkII.

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Figure 3-4: Ascom 9d24 MkII

The d62 is a new generation of handsets from Ascom. Ascom d62 provides easy interaction with colleagues and systems, with smooth administration by application of smart solutions, such as Centralized Management. Both models provide advanced messaging functions, up to 10 profile modes with customizable settings, and 3 programmable soft keys for each profile, which can be used to push data to the Ascom UNITE system.

Figure 3-5: Ascom d62

The Ascom Location Device

The DECT location devices are based on the DECT standard. The 9dLD location devices pick up and locate wireless DECT devices and store location information when the device changes its location. The 9dLD location device only works with the DECT devices in which the location feature has enabled.

The 9dLD devices continually transmit location information and RSSI (Radio Signal Strength Indicator) value to the base station. The wireless device that picks up the signal compares the radio signal from the 9dLD device with received RSSI value. Based on if the radio signal is equal or stronger than the RSSI value, the location is considered as being valid and stored by the wireless handset. Two location codes are stored in order to get information about direction of movement. When an alarm is sent, the two last stored location codes and the time elapsed since they were received, are transmitted to the alarm server. This can be used to locate the last position of the wireless device.

26 IP-PBX

Public Branch eXchange (PBX) server, also known as public Business Exchange server, is a telephone exchange system. The PBX is the internal phone server which enables the

connection between a public phone line and the phone extensions within the office or, in this case, the hospital. The main functionalities of the PBX system include: management of phone extensions, voice mail, call routing based on user phone status and call parking.

The Ascom IP-DECT system is connected to the IP-PBX, in this case trixbox.