1.双绞线：
电线成对绞在一起。每对将由用于正数据信号的导线和用于负数据信号的导线组成。在该对的正/负线上出现的任何噪声都将在另一根线上发生。由于电线的极性相反，因此它们的相位差为180度(180度或相反极性的定义)。当两条线上都出现噪声时，它会在使用的接收器处将自身抵消或消除。
双绞线电缆有两种类型–
- 屏蔽双绞线电缆–
双绞线电缆最有效地用于使用平衡线传输方式的系统中。带屏蔽的电缆称为屏蔽双绞线电缆，通常简称为STP。 - 非屏蔽双绞线电缆–
没有屏蔽的电缆称为非屏蔽双绞线电缆或UTP。将电线绞在一起会导致电缆的特性阻抗。 UTP电缆用于以太网。
2.同轴电缆：
同轴电缆由两个导体组成。内部导体包含在绝缘体内部，其他导体围绕绝缘体编织，从而提供了屏蔽。称为护套的绝缘保护涂层覆盖了外部导体。外部屏蔽层可保护内部导体免受外部电信号的影响。外导体和内导体之间的距离加上用于绝缘内导体的材料类型决定了电缆的性能。
3.光纤电缆：
光纤由细玻璃纤维组成，该玻璃纤维可以在可见光谱的频率下承载信息。典型的光纤由非常窄的一束称为包层的玻璃组成。典型的芯直径为62.5微米。
通常，包层的直径为125小镜。覆层的涂层是一种由塑料组成的保护性涂层，称为外套。生成消息的设备将其以电磁方式从(电信号)发送出去。必须将其转换为光以通过光纤电缆发送。
双绞线电缆，同轴电缆和光纤电缆之间的区别
| Characteristics | Twisted pair cable | Co-axial cable | Optical fiber cable |
|---|---|---|---|
| Signal transmission | Takes place in the electrical form over the metallic conducting wires. | Takes place in the electrical form over the inner conductor of cable. | Takes place in an optical form over a glass fiber. |
| External magnetic field | Affected due to external magnetic field. | External magnetic field is less affected . | External magnetic field is not affected. |
| Cause of power | Power loss due to conduction and radiation. | Power loss due to conduction. | power loss due to absorption, scattering and bending. |
| Bandwidth | Twisted pair cable has low bandwidth. | Co-axial cable has moderately high bandwidth. | Optical fiber cable has very high bandwidth. |
| Electromagnetic interference(EMI) | EMI can take place. | EMI is reduced to shielding. | EMI is not present. |
| Installation | Easy installation. | Fairy easy installation. | Difficult to install. |
| Attenuation | In twisted pair cable has very high attenuation. | In co-axial cable has low attenuation. | In optical fiber cable has very low attenuation. |
| Data rate | Twisted pair cable supports low data rate. | Moderately high data rate. | Very high data rate. |
| Noise immunity | Twisted pair cable has low noise immunity. | Co-axial cable has higher noise immunity. | Optical fiber cable has highest noise immunity. |