Checking The Installation - ASCOM Ascotel 2025 System Manual

9

Checking the Installation

Carefully check the following points to prevent any malfunctions.
Loop Resistance of the Analogue Exchange Line
1. Determine and record the loop resistance or attenuation.
2. Configure the attenuation of the analogue network interfaces (network card
TC-04AB) accordingly:
Attenuation £ 2 dB or loop resistance R £ 200 W : "Short" or "Short D"
Attenuation > 2 dB or loop resistance R > 200 W : "Long" or "Long D"
S Bus
• Have the terminating resistors been fitted to the last socket-outlet on the S
bus?
• Are the values for the resistors used correct? (100 W )
• Are all cable screens conductively connected to the PBX housing or the main
distribution board / patch panel?
Protective Earth and Equipotential Bonding
• Does the installation comply with the earthing concept? (See "Earthing",
Page 4.9.)
Checking for earth loops:
1. Disconnect the PBX from the power supply and UPS.
2. Disconnect the earth connections (yellow / green) on the PBX and the main
distribution board / patch panel.
3. Connect the ohmmeter between the earthing terminal on the PBX and the
building potential or between the PBX and the main distribution frame / patch
panel (see Fig. 4.85).
The resistance should be greater than 1 M W .
4. Remove the ohmmeter.
5. Reconnect the earth connections on the PBX.
6. Reconnect the PBX to the power supply.
HBT_20321104_04/B0_en
ascom Ascotel 2025/2045/2065
Checking the Installation 4.123