It is recommended that you use a cable with a maximum resistance of 5 milliohm for the ground connection.

 

AREFand GND are connected at a single point inside the wireless

NOTE

modem. They must not be joined together in your application.

7.4.2.3 Audio

Use a coupling capacitor in AUXI line if the application does not use the wireless modem’s bias voltage. See also Figure 5.9-1 Microphone connections to the wireless modem, page 52.

7.4.2.4 Software Upgrade

There are two ways of updating the firmware in the GR64. There is a web-based tool that can access a Sony Ericsson server from where SW can be downloaded. There also is an Updater, which is a local application that downloads an image provided by SEMC.

7.5 Antenna

7.5.1 General

The antenna is the component in the users system that maintains the radio link between the network and the wireless modem. Since the antenna transmits and receives electromagnetic energy, its efficient function will depend on:

•Type of antenna (for example, circular or directional)

•Placement of the antenna

•Communication disturbances in the vicinity in which the antenna operates

In the sections below, issues concerning antenna type, antenna placement, antenna cable, and possible communication disturbances are addressed.

In any event, users should contact their local antenna manufacturer for additional information concerning antenna type, cables, connectors, antenna placement, and the surrounding area. Users should also determine whether the antenna needs to be grounded or not. Usually, a local antenna manufacturer should be able to design a special antenna suitable for the integrators application and environment.

7.5.2 Antenna Type

Users should ensure that they choose the right type of antenna for the wireless modem.

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