IEC 61753-031-2:20 14包含非波长选择性分支器件（NWBD）应满足的最低初始测试和测量要求以及严重性，以便被归类为符合本IEC标准的要求。这些要求涵盖用于IEC C类环境（N是分支端口的数量）的平衡双向非连接器单模1xN和2xN非波长选择性分支设备，特别是但不限于用于PON应用。对于平衡NWBD，考虑两个衰减和均匀性性能等级: -A类（高级类），满足更严格的要求（即用于扩展覆盖PON应用）和 -B类(标准类)用于标准应用(即，正常到达PON应用)。这些要求还包括不平衡双向非连接器化单模、非波长选择性分支器件；然而，不平衡分支器件的规格仅限于1x2和2x2器件，因为它们是最常用的。 关键词:非波长选择性分支器件（NWBD），IEC C类环境

IEC 61753-031-2:2014 contains the minimum initial tests and measurement requirements and severities which a non-wavelength selective branching device (NWBD) should satisfy in order to be categorized as meeting the requirement of this IEC standard. The requirements cover balanced bidirectional non-connectorized single-mode 1xN and 2xN non wavelength-selective branching devices for use in an IEC Category C environment (N is the number of branching ports), especially but not exclusively used for PON application. For balanced NWBD two attenuation and uniformity performance classes are considered:
- class A (premium class) which meets more restrictive requirements (i.e. for extended reach PON application) and
- class B (standard class) for standard application (i.e. normal reach PON application). The requirements also cover unbalanced bidirectional non-connectorized single-mode, non-wavelength-selective branching devices; however, the specifications of unbalanced branching devices are limited to 1x2 and 2x2 devices because they are the most commonly used. Keywords: non-wavelength selective branching device (NWBD), IEC Category C environment