Potential drawbacks to VoIP phone systems

The two main drawbacks to VoIP phone systems are the network requirements and the potential for outages.

Network demands
One challenge to maintaining IP call quality is bandwidth: high quality sound requires quite a bit of it. Add to that the fact that once you move to a VoIP system, you’re now running all your business communications over one network. This means that the bandwidth used to access databases, work files, e-mail and the Internet is now sharing the same space as your voice communications.

The technology to compress audio and to reconstruct it improved to the point where VoIP sound quality over a high-bandwidth connection is as good as or better than that of regular phones. But some networks that are fine for data are not up to the demands of VoIP.

Computer networks are designed to handle messy data: packets arrive out of order and some are even lost, but in most cases the data being sent can easily be reconstructed before it is needed. Voice conversations, though, are not as tolerant of these kinds of disturbances.

Instead, each packet of sound has to arrive in the correct order because they are being sent in real time – if packets are lost, the conversation sounds distorted, choppy, or falls off all together. This is why VoIP services that rely on the Internet to transmit calls can have uneven phone quality.

If your company will be routing calls over private data networks, much of this potential problem is avoided. Companies shopping for VoIP generally have networks suitable for high-quality voice conversation – frame relay networks are ideal, but standard Ethernet networks are fine. However, they may need to be boosted with a Quality of Service (QoS) application.

QoS maintains a dedicated amount of bandwidth for voice calls by giving voice data a higher priority as it is trafficked through the network. If there is network congestion, VoIP data is routed through first so call quality does not suffer. QoS applications are built in to some VoIP systems, as well as some routers. They can also be purchased separately as upgrades.

From every indication, running VoIP on a company network without QoS is a risk no business should take. If you have a WAN that routes data over the Internet, you can still run QoS, but there can be no guarantee of quality. Internet call quality can reportedly be improved if the various offices use the same Internet service provider.

Outages
Unlike regular phone systems that get set up and basically forgotten, VoIP systems require more attention. Like any software application, your VoIP server will require occasional upgrades and maintenance.

Since regular phones get all the power they need through the phone line, they continue to work if there is a power outage. In contrast, most VoIP phones need to be plugged into a power source to work.

By definition, VoIP phones are also network-dependent. To businesses where phone service is absolutely critical, this can be a concern since computer networks can occasionally be brought down by a server crash or other problem. However a good IT staff can prevent most outages and react quickly when one occurs.

Potential outages are another reason why having a mix of digital and VoIP can be advantageous: it creates a more comfortable level of redundancy. Companies that have backup power systems in place can keep their PBX running, and the digital phone system within the main office will continue to operate even if the data network is unavailable.