The specific criteria compliance depends initially upon the expected “ship-to” location of the application. For example, telecommunication equipment being sold to a RBOC (Regional Bell Operating Company) in the USA would require NEBS compliance. This in turn requires a product to be appropriately compliant to GR-1089-Core Issue 6. China has a series of telecommunication requirements that start with YD/T, which are very similar to the ITU-T recommendations and the UL/IEC/EN 60950-1 safety standard. The IEC 61000-4-2/4/5 are also used in both South America and Europe, depending on the specific customer and the customers preference. As the application varies from “inside a building only (intra-building)” to “outside and inside (inter-building)”, so the required compliance level will change. Inter-building applications will have higher surge resistibility levels, while antenna mounted equipment will have even higher surge level resistibility levels.