悄悄地问一下：电话机属于几类设备？
电话机应该是TNV电路供电，该属于几类设备呢，为什么？请各位大侠指教。 通讯类器材认证 1.2.4.2
CLASS II EQUIPMENT
equipment in which protection against electric shock does not rely on BASIC INSULATION only,
but in which additional safety precautions, such as DOUBLE INSULATION or REINFORCED
INSULATION are provided, there being no reliance on protective earthing
1.2.4.3
CLASS III EQUIPMENT
equipment in which protection against electric shock relies upon supply from SELV CIRCUITS
and in which HAZARDOUS VOLTAGES are not generated
NOTE For CLASS III EQUIPMENT, although there is no requirement for protection against electric shock, all other
requirements of the standard apply.
根据这个定义，有可能是二类，也有可能是三类，取决于你供电是TNV还是SELV了。 楼主确认是TNV电路供电吗？那就是二，三类，具体就看是否超出SELV限值了
如果是IP电话，带适配器供电的话，按适配器划分类别 电话机属于CLASS III EQUIPMENT。
1.带适配器（输出在SELV 范围）
2.不带适配器，直接插电话线（通过通信网络供电） 引用第3楼June.Zhao于2011-05-06 16:37发表的:
楼主确认是TNV电路供电吗？那就是二，三类，具体就看是否超出SELV限值了
如果是IP电话，带适配器供电的话，按适配器划分类别
TNV供电也属于三类 引用第5楼353846835于2011-05-06 17:19发表的:
TNV供电也属于三类
TNV供电也属于三类吗？ 有没有标准依据啊，想看看。
TNV电路也算是危险电压啊
1.2.8.6
HAZARDOUS VOLTAGE
voltage exceeding 42,4 V peak, or 60 V d.c., existing in a circuit that does not meet the
requirements for either a LIMITED CURRENT CIRCUIT or a TNV CIRCUIT 虽然A TNV CIRCUIT is considered to be a SECONDARY CIRCUIT in the meaning of this standard.
那TNV2和3超过SELV限值了 引用第6楼安规007于2011-05-06 17:24发表的:
TNV供电也属于三类吗？ 有没有标准依据啊，想看看。
TNV电路也算是危险电压啊
1.2.8.6
HAZARDOUS VOLTAGE
.......
CLASS III EQUIPMENT
equipment in which protection against electric shock relies upon supply from SELV CIRCUITS
and in which HAZARDOUS VOLTAGES are not generated
HAZARDOUS VOLTAGE: voltage exceeding 42,4 V peak, or 60 V d.c., existing in a circuit
that does not meet the requirements for either a LIMITED CURRENT CIRCUIT or a TNV CIRCUIT
所以TNV电路时没有HAZARDOUS VOLTAGE。
此外，我们的一份报告也是这样写的 这个问题确实值得讨论
TNV-3电路已经超过了SELV了，所以应该归不到三类吧
但是二类也不像，因为电话机的防电压只有基本绝缘
