 is responsible for repair/replacement of the units. BSC and Transcoder Hardware Maintenance Hardware Monitoring BSC maintenance requires a site visit to perform some verifications and tests. Via the MML a connection is established between the BSC and an ordinary laptop at the BSC location. This laptop plays the role of a deported OMC. All operations are possible via this connection. MML tests on the main units of the BSC help to identify any dysfunctions. The software version of the BSC, BTS and Transcoder is also checked and a backup mechanism is verified. Alarms investigation and analysis help to localise and define the problem. It is not always a matter of unit replacement. At the Transcoder level, the most important check is the exchange terminals labelling, which indicates to which BSC each card is connected. The environment of the BSC or the Transcoder is important to check: power supply, air conditioning, external alarms, etc. BSC Load Calculations Depending on the vendor, each BSC has special hardware and capacity limitations. This indicates a special handling and monitoring of the BSC load. The objective of such a follow-up is to prevent system overload and at the same time guarantee a good quality of service. The BSC load calculation means identifying the percentage of use of each capacity item. Capacity items are: Number of TRX Number of BTS Number of traffic channels Number of exchange terminals The idea of a good dimensioning is to estimate which of these items introduces the biggest usage. This percentage corresponds to the load of the BSC. Antenna System Maintenance The antenna is an active element that adds a certain gain to the received power from the BTS. In fact, the power at the BTS connector experiences cables and connectors loss along the antenna line. The connections are normally tied to a certain pressure. When the optimisation team suspects a power de- crease, it is worth checking the connections. To detect such an anomaly a special tool measures the standing wave ratio (SWR). This metho