NEBS (Network Equipment-Building System)是电信行业专业术语，表示网络设备构建系统。它是贝尔实验室在70年代提出的一个概念，旨在帮助电话设备制造商了解服务供应商的需求和环境。它已经发展到一组规定电信环境中电信级设备可操作性的规范或测试。 NEBS 描述了典型本地贝尔运营公司（RBOC）中心局的环境。它包括空间和环境标准。它描述了典型电信设备的排列安放和设备所处的工作环境。
NEBS 的历史可以追溯到70年代，当时它由贝尔实验室开发，被用于标准化被最终安装到中心局的设备。其目的是让设备商更容易地设计兼容于典型本地贝尔运营公司的设备。标准化导致开发费用的降低和更容易将新设备引进到网络中。
那么NEBS主要组成规范文件有哪些呢?
主要的贝尔核（Bellcore）是 GR-63-CORE， 网络设备建造系统(NEBS)要求：物理保护。
这个文件确定了用于安装到本地贝尔运营公司中心局的新电信设备最小空间和环境标准。
安装空间要求：
* 缆线分布系统
* 分布和互联框架
*t电源设备
*操作支持系统
*缆线增强设施
工作环境要求：
* 温湿度
*防火性
*设备操作性
*抗震性
*工作环境振动和运输振动
* 空气污染
* 声学噪音
* 照明
NEBS认证标准分为三种级别，每个级别有自己的目标和用途，但第3级确保最大的设备可操作性，用于关键网络设备。 X335和x343提供符合NEBS 第3级标准的产品。What is "NEBS Level 3"? "NEBS Level 3" is a term from Bellcore special report, SR-3580. This report details 3 distinct functional levels of NEBS compliance based on GR-63-CORE and GR-1089-CORE. The levels allow a wide range of NEBS requirements to be applied to equipment based on application and network impact.
NEBS第1级是指设备通过了确保网络设备中安全部署的一系列最小测试。"NEBS Level 1" means that people and equipment hazards and network degradation are minimized. NEBS Level 1 addresses the personnel and equipment safety requirements of GR-63-CORE and GR-1089-CORE. This is useful for getting prototypes into a lab trial. It's also a requirement that is imposed on Competitive Local Exchange Carriers (CLECs) in order for them to deploy equipment into an RBOC's network. This level doesn't address operability, this is addressed in Levels 2 and 3.
NEBS第2级提供网络设备中设备可操作性的有限保证。"NEBS Level 2" addresses equipment operability, but in a controlled environment. For example, equipment could be used in a data center, however, if the equipment performs non-critical operations it could be used under environmental extremes. Note that this level is very rarely used because it is ambiguous.
NEBS第3级（最苛刻的 “压力”测试） 提供网络设备中设备可操作性的最大保证。
"NEBS Level 3" means the equipment is in the network for the long haul. We're talking about Carrier Class with this stringent level. The equipment will operate under the environmental extremes found in a central office. In a nutshell, the equipment meets all of the requirements of GR-63-CORE and GR-1089-CORE.
NEBS标准 – 一组基本的设备规范，设计用于：
** 确保设备与电话行业的电子环境的兼容性
** 简化设备规划和安装
** 保护电信设备不会出现由于不兼容设备导致的业务宕机
** 防止干预许可的无线电发射机和其它极其类似的电信设备
** 最大限度地降低电信设备发生火灾的风险
** 确保设备在电信环境中规定的温度、湿度、振动、空气污染范围内运行
** 确保地震情况下设备和业务的可抗损毁性
** 保护员工免受伤害
Bellcore（Bell Co mmunications Re search, Inc）成立于1984年，由AT&T中的中心服务组织剥离而成立。1997年，Bellcore被SAIC(Science Applications International Corporation )公司收购更名为Telcordia. NEBS标准1997年前由Bellcore拥有，1997年之后由Telcordia保有。
NEBS认证可由开展测试认证服务的检测机构提供，如MORLAB(摩尔电信实验室).
认证测试项目如下：
Test Item
Spatial 安装空间
Low Temp Storage 低温存储
High Temp Storage 高温存储
High R/H Storage
Op Temp/Humidity(Hardened Criteria)
Altitude Test
Fire Spead
Needle Flame
Packaged Drop 跌落测试
Office Vib
Earthquake Simulation Test 地震模拟测试
Transportation Vib 运输震动
Earthquake Simulation Test
Transportation Vib
Hygroscopic Dust
Mixed Flow Gas(Outdoor Level)
Acoustic Noise 噪音
Illumination
Heat Dissipation
Temp Margin Test 温度裕量
Fan Failure
Surface Temp
Trans Vib(GR-3108)
Cold Start at -40 Deg C(GR-3108) -40°C冷启动
Temp/Humidity Cycle(GR-3108)
Power Interface Req(AC and DC)
Salt Fog UUT(180 hrs of exposure)
Low Level Vib Resistance
ESD 静电放电（Electrostatic discharge）
EFT 电快速瞬变脉冲群(Electrical fast transient burst)
Conducted Emissions 传导干扰
Radiated Emissions 辐射干扰
R&D Radiated Emissions(Repeat w/ all units)
R&D Radiated Emissions(Repeat w/ all units)
Radiated Immunity
Conductive Immunity
Short-Circuit Test
First Level Lightning Surge 雷涌
1st Level Lighting Protection
2nd Level Lightning Protection
Indra Building Lightning
First Level AC Fault
Current Limiting Protection
Second Level Power Fault
Lightning Protection
Short Circuit
Lightning Criteria
Steady State Power Induction
DC Potential Difference
Electrical Safety
Corrosion
Bonding & Grounding
DC Power Test 直流电源测试
Then you can added ETSI Test
For ex.
Test Item
ETSI Package Bump Shock 包装撞击
ETSI Operational Shock
ETSI Change In Temperature
ETSI Water Test(6mm/min for 15 min,for ex.)
ETSI Damp Heat Cyclic 湿热循环
ETSI EFT-AC Port 交流电源
ETSI Radiated Emissions EMI
ETSI Conducted Emissions-DC Ports
ETSI Conducted Emissions-Ac Ports
ETSI Harmonics
ETSI Flicker(AC)
ETSI RF Conducted Immunity
ETSI Surge Test(AC) 浪涌
ETSI Voltage Dips/Interruptions
ETSI Power Freq-Magnetic Field