BusinessPhone Communication Platform 4.0
Installation Instruction ASB 150 02 > Integrated Cordless

## Base Station (KRCNB 201 03/_ and KRCNB 301 03/_)

The Base Station (BS) enables radio communication between the Integrated Cordless system and the portable telephones. The communication via two 2B+D interfaces, requires two twisted pair cables. Both interfaces provide in total eight 32 kbit/s speech paths between a BS and IC-LU, enabling a BS to handle eight simultaneous calls. The BS is connected to the IC-CU2 or IC-LU via two wire pairs called serial communication wires (SC0 & SC1) carrying up to 8 simultaneous digital voice connections and the central power feeding. Apart from data communication these two twisted pairs are also be used to distribute power to the BSs. Two additional pairs can be wired to provide a greater powering range. There are three methods to power BSs:

- centrally via backplane (with or without EPP)
- centrally via external input (with / w.o EPP)
- via local power supply (optional).

With the first and second methods power is distributed via the IC-LU to the BS. The cable length between BS and IC-LU depends on the number wires used for power feeding, the type of cable and environmental noise. In the third case (local feeding), BSs are powered by an AC-adapter or another power source which is not routed via the cabinet.

The number of BSs used in a system depends on the area to be covered and the traffic density. Typical in-house coverage is up to 30 meter radius. In practice the cell size may vary between 10 meters indoors in worst case situations, up to 300 meters outdoor in free space.

The BS has two main functions:

- to modulate a carrier with the digital encoded information (TDMA frame directed to portable)
- to demodulate a modulated carrier (TDMA frame received from portable).

A special cover (KRY NB 101 01) is available to mount the BS (KRCNB 201 03) outdoors providing splash proof housing and water tight sealings for the wiring.

#### Base Station Planning

The major task when providing a wireless service is to estimate the number of BSs and to find their most suitable location. A number of factors tend to limit the range of a BS like the materials the wall is composed of or the location and size of machines, furniture, air-conditioning systems, elevators etc. This results in unexpected reflections or absorption of radio waves. Generally BSs should not be located on outer walls, except if the outdoor area has to be covered as well, as this reduces the area actually covered. All of these unpredictable influencing factors makes it extremely difficult to define rules for how to cover an area with a suitable number of BSs. In difficult environments the use of a site survey tool (LTT NB 101 01/_) is recommended.

Establish a Base Station plan for the installation site to determine the best location for the BSs.

#### Base Station aerial range

- In an office environment in a steel concrete building up to 30 m in diameter can be covered and including, under normal conditions, the neighbouring floors.
- Production halls up to 200 m in diameter are covered but ranges can be less if bulky machines, cranes etc. are part of the interior.
- Outdoor ranges can be up to 300m.

When installing a BS, position it, then walk around to determine cell coverage area either by listening to the speech quality - whether mutes or crackling sounds are heard in the portable - or measure the RQI indicator using the portables Service Display facility (see Fault Tracing, 1545-ASB 150 02 Uen).

#### Base Stations Cabling

Using a four-pair cable or more-pair cable, the free cable pairs can be used as additional power wires (EPP) to increase the feeding distance and reduce overall power consumption (by reducing the ohmic resistance) to the BS. The BSs can also be powered by an on-site adapter (refer to Power Feeding of Base Stations).

Connection of serial communication wires and EPP lines is polarity-independent. SC0-0 and SC0-1 may be interchanged but SC0-x and SC1-x may not be interchanged. The diagram below shows the wiring principle to each base station connected to the IC-CU2 or IC-LU.

#### Power feeding of the Base Station

There are three alternatives to power feed (-48V) the Base Station:

- The power feeding can be taken via the IC-CU2 or IC-LU from the back plane in the cabinet. The DIP-switch on the IC-LU is set to OFF.
- From an external power source via the front connector on the IC-CU2 or IC-LU (£56V). Note the polarity on the input (see drawing of IC-CU2 or IC-LU board). The switch on the IC-CU2 or IC-LU is set to ON.
- By an AC-adapter (see Power Feeding of Base Stations). The switch on the IC-CU2 and IC-LU should be set to ON but no power feeding from the external power source via the front connector on the IC-LU.

#### Base station cable delay measurement

After all base stations have been installed, the cable delays must be measured in order to program the base station delays into the system at initialization time. On IC-LUs with the revision R1D and higher and IC-CU2 revision R1C or higher automatic delay measurement is performed. In this case no measurement is needed but using the cordless system manager (CSM) go to the menu "add Base Station" and enter a "1" in the field "delay".

Base station delays are measured at the radio exchange with an echo-meter connected to cable data pair SC0 or SC1 and with the cable open ended at both sides. So the cable must be disconnected from the IC-LU or IC-CU2 as well as the base station.

1. Make sure that the base station cable is unplugged from the base station and the relevant connector on the relevant IC-LU or IC-CU2.
2. Connect an echo-meter to cable pair SC0 or SC1.
3. Measure the cable delay. The measured delay is the time between sending a pulse down the line and receiving the echo. Therefore the recorded value is twice the cable delay and must be halved. The resulting value must have an accuracy of 200 ns (corresponding with 20 – 30 m).
4. Record on paper the delay value measured for each base station in microseconds, together with the base station number.
5. Repeat the delay measurement for all base stations.
6. Re-connect the connectors to the IC-LU or IC-CU2.

Another possibility is measuring the ohmic resistance:

- Connect to SC0 or SC1 measure the resistance of the loop and divide the result by 3,3. This is the value to be entered at system initialization in the Cordless System Manager.

- This formula applies for wires of 0.5 mm diameter. After all lines to the Base Stations have been measured, connect the Base Stations by plugging-in the connector.

#### Ranges on cables

The following ranges are given for base stations connected to an IC-CU2 and IC-LU. Depending on the cable type ranges depend on noise levels imposed on the cables. The values stated are maximum achievable ranges:

Cable Type | Wire diameter (Æ) | Capacitance | Maximum cable length with Superimposed noise
8 mV/pHz | 10 mV/pHz
Twisted pair | 0.4 mm | 45 nF/km | 1.2 km | 1.0 km
Twisted pair | 0.5 mm | 45 nF/km | 1.6 km | 1.4 km
Twisted pair | 0.5 mm | 120 nF/km | 0.9 km | 0.8 km
Twisted pair | 0.6 mm | 45 nF/km | 1.9 km | 1.7 km
Twisted pair | 0.6 mm | 120 nF/km | 1.1 km | 1.0 km
Double twisted pair (J-Y (St)Y 2´2´0.6) | 0.6 mm | 120 nF/km | 1.0 km | 0.9 km

#### Base Station (KRC NB 203 01/_)

The Base Station (BS) is supplied with a drilling template to mount the unit and 2 antennas with TNC connectors. Mount the unit in a suitable location to provide the best communication coverage.

Use the supplied drilling template and mount the BS with four screws (6 mm Æ). Complete the electrical connection according to the above drawing. Do not connect to the Base station yet.

If power is supplied by the adapter (BMLNB 101 04), the screw/slide connector must be used. The serial communication wires can be connected via the modular jack or the screw/slide connector. A screw with a bundling cord holder is provided for traction relief to the left of the connection field.The BS starts up if the supply lines deliver more than 12 VDC.

Note

If the Base Station (KRC NB 201 03/_) is accessible by persons other than trained personnel mount the cover (SDFNB 101101/_ or similar).

#### Base Station (KRCNB 301 03/_)

The BS is connected to the radio exchange by means of a standard twisted pair cable. The BS is can be fixed to a wall, a ceiling, a pole or a beam, by means of the mounting bracket included. When fixing the BS to a wall or ceiling the included plugs and screws must be used. When fixing it to a pole or beam a (not included) strap or a flexible metal band must be used.

##### Connectors

- Two 8-pin modular jacks for data and powering
- A 6-pin modular jack for factory testing

The two data/powering connectors are interconnected on the board.

##### LEDs

LED 1: Green power LED |  |

LED 2: Three colour LED, see table below
Status of LED2 | Meaning
Off | Base station operational and no traffic on the base station
Green | Base station operational and traffic on the base station
Red | Base station is malfunctioning
Amber | Base station is OK, but not available (self-test, not initialized, no communication with radio exchange)
Flashing green | All 8 channels are in use
Flashing amber | Software is being downloaded to the base station

The BSs can be mounted vertically or horizontally. Mount the BSs at places and positions as determined in the system configuration plan. The BS must be placed so that it is not facing large metal objects such as large heating pipes, machines.

##### Fixing the mounting bracket to a wall

Fix the mounting bracket (see figure below) to the wall as follows:

1. Hold the mounting bracket with its flat side against the wall such that the text ‘TOP’ is the right way up, and mark the two holes. The minimum distance between the upper hole and the ceiling or any object above the BS must be as least 65 mm. If the distance is less than 65 mm, the BS cannot be slid onto the bracket.
2. When using wall plugs, take a Æ 6 mm drill and drill the two holes and insert the included wall plugs.
3. Position the mounting bracket with its flat side to the wall and fasten it with the two included Æ 3.5 mm screws.

##### Fixing the mounting bracket to a pole or beam

The mounting bracket can be attached to a pole (diameter ³ 45 mm) or a beam (wider than 50 mm) by means of a strap or flexible metal band less than 30 mm wide. Position the mounting bracket to a pole or a beam so that the text ‘TOP’ is right way up. The strap or flexible metal band must be purchased locally.

##### Cable ducts

When the BS is mounted to the wall, cable ducts can be used to route the wiring through.

- Fix the cable duct to the wall in one of the positions shown in the left figure.
- For safety reasons secure the BS cable to a convenient point at about 30 cm from the base station.

If for some reason the BS drops, the cable is pulled out of the base station.

##### Mounting the Base Station

Hold the BS flat against the mounting bracket and move it downwards until it clicks.

Note

After completion of the installation, base stations must be initialized using the cordless system manager.

#### Power Feeding of Base Stations

When using any of the adapters mentioned below care must be taken to configure the IC-CU2 boards for local BS feeding. If the BSs are to be fed locally the remote power feeding switch on the boards should be set to the position disconnecting the feeding from the back plane and no external feeding to the board should be connected.

##### Adapter for Base Station (KRCNB 201 03/_)

An AC-adapter to feed the BS locally is available for 230VAC/24VDC (BMLNB 101 04) for all European countries except for the UK and Cyprus. In other countries it has to be purchased locally and must meet the specifications given below:

- Output voltage: between 12 V and 56VDC
- Output power: 7.5W minimum

##### Adapter for Base Station (KRCNB 301 03/_)

The 24 VDC adapter (BMLNB 101 09/n) is fitted with a 8-pin modular plug that can be plugged into one of the data/power connectors of the base station.

#### Software upgrade

If necessary, the software in the BS can be updated by downloading new software to the BS. Downloading can be performed without disconnecting the BS. The new software is stored in flash memory.

Revision: A © Ericsson Enterprise 2003