VoIP Phone Systems for Small Business: Cost, Network, E911

A VoIP phone system carries your business calls over your internet connection instead of traditional phone lines. For most small businesses the practical choice is a hosted (cloud) service, with published prices from major providers running from about $10 to $30 per user per month as of September 2026. Each call needs only around 100 kbps in each direction, so raw internet speed is rarely the obstacle. What decides call quality is delay, jitter, and packet loss on your own network, and what you must not skip is registering accurate 911 locations and planning the number port.

How Does a VoIP Phone System Work?

VoIP stands for Voice over Internet Protocol. When you speak, the phone or app uses a codec (a method of converting and compressing audio) to turn your voice into small data packets, typically one every 20 milliseconds. Those packets cross your office network and the internet to your provider, which connects the call to the regular telephone network. A separate signaling conversation, usually a protocol called SIP, handles ringing, answering, transferring, and hanging up.

Because the phone is now a network device, it can be a desk handset, an app on a computer, or an app on a mobile phone, all ringing on the same business number. It also means call quality depends on your network in a way it never did with copper lines.

Hosted or On-Premise: Which Fits a Small Office?

A PBX is the system that routes calls between extensions, menus, voicemail, and outside lines. With VoIP it can live in the provider’s cloud or on a server in your office.

	Hosted (cloud) PBX	On-premise PBX
Where the system runs	Provider’s data centers	A server or appliance in your office
Cost shape	Per user, per month	Hardware and setup upfront, plus outside lines (SIP trunks) and maintenance
Who updates and secures it	The provider	You or your IT support
Remote and mobile staff	Built in	Possible, needs secure remote access
If your office loses power or internet	Calls can still reach mobile apps and voicemail	The whole system is unreachable unless you planned failover
Best fit	Most small businesses	Sites with special integrations, many internal extensions, or existing investment

For a business with fewer than a few dozen users, hosted is usually the simpler and more resilient choice. On-premise still makes sense where a specific integration or an existing system justifies it.

How Much Bandwidth Does Each Call Use?

Less than most people expect. Cisco’s reference on per-call bandwidth puts a call using the common G.711 codec at 87.2 kbps over Ethernet including all packet overhead, and a call using the compressed G.729 codec at 31.2 kbps. Microsoft’s network guidance for Teams lists 58 kbps as the recommended figure for audio and 76 kbps for best performance.

A safe planning number is 100 kbps per simultaneous call, in each direction. Ten people on the phone at once is about 1 Mbps up and 1 Mbps down.

So why do calls sound bad on fast connections? Because voice is sensitive to timing, not volume:

• Latency is how long a packet takes to arrive. Cisco’s summary of ITU recommendation G.114 gives 0 to 150 ms one way as acceptable for most uses. Beyond that, people start talking over each other.
• Jitter is variation in that delay. Phones smooth it out with a small buffer. When jitter exceeds the buffer, words drop out.
• Packet loss produces the choppy or robotic sound. Voice packets are not re-sent, because a late packet is useless.

The usual trigger is upload congestion. Many cable internet plans have far less upload than download capacity. One large cloud backup or file upload fills the upload queue in the router, and voice packets wait behind it.

What Is QoS and Do You Need It?

QoS (quality of service) tells your network equipment to send voice packets first when there is a queue. Phones and apps mark voice packets with a priority label called DSCP, and switches and the router honor it. Microsoft’s QoS guidance for Teams uses DSCP value 46 (Expedited Forwarding) for audio, which is the conventional marking for voice.

Microsoft’s own advice is measured: “A small business with few users might not need QoS, but should consider it if experiencing network delays.” That matches the practical order of work:

1. Wire desk phones instead of running them on Wi-Fi.
2. Fix the upload bottleneck at the router. Turn on the router’s QoS or smart queue feature, set to slightly below your real upload speed, so voice is prioritized where congestion actually happens.
3. Put phones on a voice VLAN. It separates call traffic and makes priority rules simple. See our network segmentation guide.
4. Schedule heavy uploads such as backups outside business hours.
5. For calls over Wi-Fi, make sure the wireless network is solid first. Our office Wi-Fi troubleshooting guide covers roaming and congestion, which hurt calls before anything else.

QoS only works inside the network you control. Once packets reach the public internet, every packet is treated equally. That is why the quality of the internet connection itself still matters. Also check the firewall: some routers have a “SIP ALG” feature that rewrites call signaling and causes one-way audio or dropped calls. Check your provider’s setup guide for whether it should be disabled on your router.

What Are the 911 Requirements for Business Phone Systems?

Two federal laws, enforced by the FCC, apply to business phone systems (the FCC calls them multi-line telephone systems). The FCC’s page on Kari’s Law and RAY BAUM’S Act is the primary reference.

Kari’s Law requires that anyone can dial 911 directly, with no prefix such as 9 for an outside line, and that the system sends a notification to a central location or designated person (a front desk, a manager’s phone or email) when a 911 call is made. It applies to systems manufactured, imported, offered for first sale or lease, first sold or leased, or installed after February 16, 2020.

Section 506 of RAY BAUM’S Act requires that a “dispatchable location” reaches the 911 center with the call: the validated street address plus the detail needed to find the caller, such as suite, floor, or room. Under the FCC’s rule, 47 CFR 9.16, fixed devices on the premises (desk phones) have had to provide this automatically since January 6, 2021. Devices that move around the premises, and devices used off premises such as a softphone at home, have been covered since January 6, 2022, with automatic location where technically feasible and otherwise a location the user updates.

What that means in practice:

1. Enter a complete address, including suite and floor, for every user and device in the provider’s admin portal.
2. Set up the 911 notification to go to someone who will see it.
3. Tell remote and hybrid staff that their app needs their current address, and show them where to update it.
4. Confirm 911 can be dialed without a prefix.
5. Ask your provider how to place a test without tying up a real 911 line, and do it after setup and after any office move.

The FCC also reminds VoIP users in its VoIP and 911 guide that service may not work during a power or internet outage. Keep a charged mobile phone available as the fallback.

How Long Does Number Porting Take?

Porting is moving your existing numbers to the new provider. The FCC’s porting guide says simple ports, which generally involve a single line and no complex switching changes, must be processed in one business day. A business with several lines, a main number that hunts to others, or toll-free numbers is not a simple port, and the one-day rule does not apply. Your new provider will give you a scheduled date once the old carrier accepts the request. Ask for it in writing and do not plan the cutover around a guess.

To avoid delays:

1. Do not cancel the old service. A number has to be active to be ported. Cancelling early can lose it.
2. Get a current bill and the customer service record from the old carrier. The port request must match the account name, service address, and authorized contact exactly. Mismatches get the request rejected and restart the clock.
3. List every number, including fax, alarm, elevator, and gate lines. Decide what happens to each. Ask the alarm or elevator vendor before moving those to VoIP.
4. Build and test the new system first on temporary numbers: menus, ring groups, voicemail, 911 addresses.
5. Schedule the cutover for a quiet time and confirm the firm date in writing.
6. Test on the day: inbound, outbound, main menu, each direct number, 911 location display in the portal.

What Does VoIP Cost per User?

These are prices published by the providers themselves as of September 2026. Taxes and regulatory fees are added on top, and promotional rates change, so check the linked pages.

Provider and plan	Published price	Notes
Microsoft Teams Phone Standard	$10 per user per month	Phone system features only. Needs a calling plan or an outside carrier, and a Microsoft 365 plan with Teams
Microsoft Teams Phone with Calling Plan (US)	$17 per user per month	Includes domestic calling. Annual term pricing announced by Microsoft, in effect since April 1, 2025
Google Voice Starter	$10 per user per month	Up to 10 users. Requires Google Workspace
Google Voice Standard	$20 per user per month	Adds automated call handling and ring groups, unlimited users
Google Voice Premier	$30 per user per month	Adds advanced reporting and international locations
Nextiva Core	From $15 per user per month on annual billing	Monthly billing is listed higher
Nextiva Engage	From $25 per user per month on annual billing	Higher tier aimed at managing customer interactions at volume

RingCentral and Zoom Phone also publish per-user pricing that varies with user count and billing term, so use their pages for a current figure.

Other costs to budget for: desk handsets if you want them (apps on computers and mobiles need none), a PoE switch to power handsets, any network fixes identified beforehand, and setup time. If your staff already work in Microsoft Teams all day, our Microsoft Teams guide covers how the phone add-on fits.

What Happens When the Internet or Power Goes Out?

Desk phones stop. With a hosted system the service itself keeps running in the cloud, so plan for that:

• Install the provider’s mobile app for key staff, so calls ring on cellular data.
• Set a failover rule in the portal that forwards the main number to a mobile if the office phones go offline.
• Put the modem, router, and PoE switch on a battery backup (UPS) so a short power cut does not drop calls.
• If phones are critical to revenue, add a second internet connection with automatic failover.

This belongs in your broader IT disaster recovery plan.

When Is a Full Phone System More Than You Need?

One or two people who mostly use mobiles may only need a business number that rings an app, which the entry plans above provide without any desk hardware or network changes. A full system with menus, ring groups, and handsets starts to earn its place when you have a front desk, several people answering the same number, call recording or reporting needs, or more than one location.

Common Mistakes

• Choosing a provider before checking the network, then blaming the provider for choppy audio.
• Leaving 911 addresses blank or set to the head office for remote staff.
• Cancelling the old carrier before the port completes.
• Forgetting fax, alarm, and elevator lines in the number inventory.
• Running desk phones over congested Wi-Fi.
• No plan for an internet outage.
• Sending voice traffic through a VPN. Microsoft advises against it for real-time audio. See secure remote access.

Common Questions

Can We Keep Our Existing Phone Numbers?

In almost all cases, yes. Numbers can be ported to the new provider as long as the provider serves your area and the port request matches the old account details. Keep the old service active until the port completes.

Do We Need Desk Phones?

No. Every major hosted service has computer and mobile apps, and a good headset is often the better investment. Desk phones still suit reception desks, shared spaces, and people who prefer a handset. They need a wired network port, ideally with PoE.

Is Our Internet Fast Enough for VoIP?

Probably. At about 100 kbps per call, even a modest business connection handles many calls. The better question is whether the connection is stable. Run a continuous ping test during a busy hour, as described in our Wi-Fi troubleshooting guide, and look for packet loss and delay spikes, especially while something is uploading.

Does VoIP Work for Fax, Alarm Panels, and Card Terminals?

Not reliably over a standard voice line, because these devices send tones that voice compression distorts. Options include the provider’s online fax service, a cellular communicator for the alarm panel, and a network-connected card terminal. Check with each equipment vendor before porting those numbers.

Who Is Responsible for 911 Compliance, Us or the Provider?

Both have obligations. The provider must deliver the capability. The business that installs, manages, or operates the system is responsible for configuring it correctly: direct dialing, the notification, and accurate locations for each device. The FCC page linked above sets out the roles.

How Coastal Growth Co. Can Help

We check whether your network is ready for VoIP before you commit: a stability test on the internet line, switch and PoE capacity, a voice VLAN, router QoS, and Wi-Fi where calls will use it. We can also help compare providers against how you answer calls, plan the number port, and set up 911 locations and outage failover. See our network services and cloud and email services, or contact us with your user count and current carrier. Scope and price are agreed before any paid work.