Product manual

System description, Hardware building blocks

Technical Product Manual - DCT1800-GAP

TD 92093 (1/LZBNB 103 108 R4D) / 2006-03-09/ Ver.C

The radio exchange mainly consists of:

• One to four modular cabinets

• A number of system boards

The 10 inch modular cabinet mainly contains a Modular Cabinet Connection Board (MCCB) and a

backplane with 9 system board connectors, a rectifier circuit and a DC/DC converter.

The modular cabinet has three powering options:

• External power source: e.g. a PBX powering unit of −48 Vdc

• A class II 36 Vac, 300 VA power transformer

• A battery power unit

The battery power unit consists of a −48 Vdc power supply unit that fits on the rear side of the battery

cabinet. This cabinet has room for 4 dedicated batteries that give a back-up time of 180 minutes for

a 240 W system.

3.2 Base stations

The base station enables radio communication between the radio exchange and cordless phones. A

base station communicates with the radio exchange via two 2B+D interfaces, requiring a two twisted

pair cable. Use minimum 26 AWG copper conductors.

The two 2B channels (256 kbit/s) provide eight 32 kbit/s speech paths between a base station and

radio exchange, enabling a base station to handle eight simultaneous calls. Except for data

communication these two twisted pairs can also be used to distribute power to the base stations. One

or two additional pairs can be wired to provide a longer powering distance.

The following methods exist to power base stations:

• Via local power supply

• Via the modular cabinet

With the first method, base stations are powered by an AC-adapter or another power source which is

not routed via the cabinet. The maximum cable length between base station and radio exchange is

only data limited and may reach up to 1900 metres.

With the second method, power is distributed via the cabinet and base station cabling. The cable

length between base station and cabinets now depends on the number of twisted pairs used for power,

the type of cable and environmental noise.

The number of base stations used in a system depends on the area to be covered and the traffic

density. Typical in-house coverage is a 20 metre radius. In practice the cell size may vary between 10

meters indoors in worst case situations, up to 300 metres outdoor in free space.

The air interface conforms to FCC part 15.

The base station has the following main functions:

• To modulate a carrier with the digital encoded information (TDMA frame directed to cordless

phone)

• To demodulate a modulated carrier (TDMA frame received from cordless phone)

The following types of base stations are available: