scope:

The present document sets out the major engineering requirements for telecommunications equipment forming part of a public telecommunications network installed either on public telecommunications operators' sites or in premises of operators' customers.

It is expected that the areas of transmission equipment and switching equipment will increasingly merge into one. As a result, the present document should be applied to all forms of telecommunications equipment.

The operating authorities should be given the data to help them plan buildings and building utilization, including ceiling heights, equipment and traffic areas, hallways and doors and transport installations (freight elevators, loading ramps, etc.). They also need to be able to compute the structural design requirements and the type and scope of air conditioning needed.

It should be made possible to expand existing installations and to combine equipment from different manufacturers. Therefore, operating authorities are guaranteed a wide scope for system selection.

The equipment designer should be able to derive a suitable mechanical design for telecommunications equipment.

Such a scope calls for standardization of certain levels in the mechanical hierarchy, e.g.:

• dimensions for racks, miscellaneous racks and subracks. The definitions of cabinets and racks contained in IEC publication 60917-1 [1] are:

- Cabinet: a free-standing and self-supporting enclosure for housing electrical and/or electronic equipment. It is usually fitted with doors and/or side panels which may or may not be removable;

- Rack: a free-standing or fixed structure for housing electrical and/or electronic equipment.

• accessibility of rack rows;

• cable access;

• heat load;

• static load;

• compatibility with Electro-Magnetic Compatibility (EMC) and Electro-Static Discharge (ESD) requirements.

Existing equipment practices are not covered by the present document.