Voice over Internet Protocol (VoIP) has become an essential technology for affordable voice communications.
By converting analog voice signals into digital data packets, VoIP allows for phone calls to be made over IP data networks rather than traditional analog telephone lines.
This brings great cost savings and flexibility. However, to realize the full benefits of VoIP technology, the right cabling infrastructure needs to be in place.
VoIP performance is highly dependent on using high-quality cables designed for carrying voice traffic reliably.
This article will provide a comprehensive overview of the types of cabling used for VoIP implementations.
1. Twisted Pair Cables
Twisted pair cabling is the most prevalent option for VoIP implementations. It uses copper wire pairs that are twisted together to transmit data.
The twisting helps reduce interference and crosstalk issues.
Twisted pair cabling comes in different categories, with each suited for varying network speeds and bandwidths. Let’s look at the major types:
Category 5/Cat 5
Cat 5 cable was once the popular choice for Ethernet networks and early VoIP implementations.
It supports network speeds of up to 100 Mbps and bandwidth of up to 100 MHz. However, Cat 5 is no longer recommended for VoIP since it lacks noise-cancelling capabilities.
Category 5e/Cat 5e
Cat 5e or Category 5 enhanced was developed to improve upon Cat 5 limitations. It also supports network speeds up to 100 Mbps but features more stringent testing specifications for crosstalk.
This allows it to handle bandwidth up to 100 MHz making it suitable for VoIP. Cat 5e is currently the minimum standard for VoIP cabling.
Category 6/Cat 6
Cat 6 brings further improvements by supporting gigabit network speeds up to 1 Gbps and bandwidth up to 250 MHz.
It incorporates additional noise-canceling technologies and is built to higher standards to enable these faster speeds. Cat 6 is recommended for new VoIP implementations as it future-proofs the cabling for next-generation multi-gigabit networks.
Category 6a/Cat 6a
This enhanced version of Cat 6 pushes maximum speeds up to 10Gbps and bandwidth to 500 MHz. It uses more rigorous noise mitigation and is intended for data centers and storage networks that need ultra-high bandwidth. Overkill for typical VoIP systems.
Beyond these common twisted pair varieties, the additional Category 7/ Cat 7 standard exists for 10 Gbps networks up to 600 MHz. However, it is seldom used for VoIP deployments. When selecting twisted pair cabling, key considerations include:
- Solid vs stranded core: Solid core wire is better for stationary VoIP devices since it faces less signal attenuation. Stranded core is more flexible but not as suitable for VoIP.
- Shielded vs unshielded: Cabling with shielding blocks electromagnetic interference (EMI) better. Helpful for noisy electrical environments.
- Snagless boots: These protective tips on RJ45 connectors prevent the clips from being damaged. Important for securing connections.
- Plenum rating: Plenum cables use flame retardant jackets to meet fire codes for running through ceiling ducts and plenums.
2. Fiber Optic Cables
In addition to twisted pair copper, fiber optic cabling is a popular option for VoIP systems.
Optical fiber uses pulses of light to transmit data signals digitally rather than electrical signals. There are two predominant types:
Single-mode Fiber
As the name suggests, single-mode fiber has only one core through which a single ray of light propagates.
The small core and single light wave means it can travel longer distances but requires a light source with a narrower wavelength. Single-mode is typically used for long-distance campus or WAN connections.
Multi-mode Fiber
Multi-mode contains multiple cores and can have several light waves of varying wavelengths traveling through it simultaneously.
This allows for shorter distance but high bandwidth transmission. Multi-mode is common for shorter LAN connections and inter-building links.
Beyond several modes, fiber cable is also classified by size with common options being OS1, OS2, or OM1 through OM5. A key benefit of fiber is no electromagnetic interference or current leakage, making it very secure.
Fiber can transmit data at far higher speeds and over greater distances than copper. But it also costs more than twisted pair and is harder to install and terminate.
Overall for VoIP networks, fiber cabling works well connecting buildings on a large corporate or college campus. Inside buildings, twisted pair copper wiring is adequate for most needs and more cost-effective.
Key Connectors for VoIP Cabling
With an understanding of the major cable types, it’s also important to know the common terminating connectors used with them:
1. RJ11
The RJ11 is a connector used for connecting standard telephones using a single pair of copper wires.
It features six pins and has largely been replaced by the RJ45 for VoIP phones and Ethernet networks.
2. RJ45
The RJ45 connector is the standard for twisted-pair copper Ethernet and VoIP cabling. It has 8 pins that correspond with the wire pairs and allows for gigabit network speeds.
RJ45 connectors terminate Cat 5e, Cat 6, and other twisted pair cables.
3. LC
The LC connector has displaced many larger fiber optic connectors to become the small form factor standard for fiber links. Its snap-in design makes it easy to install while taking up minimal space.
4. SC
An older fiber optic connector that utilized a push-pull locking mechanism. SC is still used in some networks but is being gradually phased out by LC.
5. ST
A bayonet-style fiber connector that featured a screw-in design. Also, it is phased out in favor of smaller and easier-to-use LC connectors.
Beyond these common options, there are various other copper and fiber connectors for specific applications like the MT-RJ, GG45, and MPO.
But RJ45 and LC cover the vast majority of VoIP cabling interconnection scenarios.
Key VoIP Cabling Standards
Several standards define structured cabling systems for commercial voice and data networks. Compliance with these standards ensures optimal performance and interoperability for VoIP:
1. ANSI/TIA-568
The Telecommunications Industry Association’s ANSI/TIA-568 standard sets commercial cabling guidelines for the US market.
It consists of several parts covering copper cabling, fiber cabling, infrastructure, and more. TIA-568 recognizes categories like Cat 5e, Cat 6, and Cat 6a and classes for fiber like OM4.
2. ISO/IEC 11801
The International Organization for Standardization (ISO) also defines structured cabling standards for data centers and offices.
ISO/IEC 11801 provides international guidance and is aligned with TIA-568 for consistent global standards.
3. TIA-569-D
This Telecommunications Infrastructure Standard from TIA covers pathways, spaces, grounding, and administration for implementing an overall structured cabling system. It is a key complement to TIA-568.
Knowing regional cabling standards like TIA-568 for North America and complying with them ensures your VoIP network copper and fiber cabling will work optimally.
Standards outline cable runs, terminations, electrical grounding, and many other aspects.
VoIP Cabling Installation and Maintenance Best Practices
Once you have selected the appropriate cables, and connectors and complied with cabling standards, proper installation is critical for reliable VoIP service. Some best practices include:
- Work with certified professionals for business VoIP cabling needs rather than trying DIY
- Follow manufacturer guidelines for bending radius, tension, etc when running cables to avoid damage
- Use velcro or other gentle fasteners instead of zip ties which can be overtightened
- Neatly dress and label cables at patch panels, submitting clear documentation
- Avoid running voice and data cabling close to power lines or fluorescent lighting to reduce interference
- Place cabling inside wall cavities or cable trays instead of laying directly on ceilings
For maintenance, regularly inspect cabling for damage after initial installation:
- Replace any frayed, cracked, or crimped cables immediately to prevent issues
- Check connectors are snugly fitted and snap-in tabs are intact
- Confirm cabling is securely fastened without overtightening ties or fasteners
- Test cable runs periodically to ensure they meet specifications
- Maintain cabling documentation with test results and any changes
Proper cabling practices will keep your VoIP phone system running reliably delivering great call quality.
Frequently Asked Questions (FAQ)
Ques 1. What are the main types of cables used for VoIP?
Ans. The two primary cables are twisted pair copper such as Cat5e and Cat6, and fiber optic cables like single-mode or multi-mode. Each offers distinct advantages depending on the network scenario.
Ques 2. What is the minimum category of twisted pair cable recommended?
Ans. Category 5e or Cat5e is the minimum twisted pair cable standard recommended for VoIP networks. It provides the bandwidth and reduced interference needed for VoIP calls.
Ques 3. What connector is commonly used for twisted pair VoIP cables?
Ans. The RJ45 connector terminates twisted pair copper cables like Cat5e and Cat6. It has 8 pins to interface with the cable’s wire pairs and enable Ethernet and VoIP connectivity.
Ques 4. When should fiber optic cable be used instead of copper?
Ans. Fiber can span greater distances and provide higher bandwidth, so it makes sense for long enterprise VoIP cable runs between buildings.
However, within buildings, copper cabling is typically adequate and more cost-effective.
Ques 5. What is the most common type of fiber optic connector used?
Ans. The LC connector is now the predominant fiber optic connector, replacing the larger SC and ST connectors. LC is a snap-in small form factor design perfect for space-constrained VoIP installations.
