How to Switch From Landline to VoIP

The short answer: Switching your business from a landline to VoIP takes 5–10 business days end-to-end. Number porting — transferring your existing phone number to the new provider — accounts for 3–7 of those days. The remaining time covers account setup, endpoint configuration, and a parallel-run test period where both systems stay active. Keep your landline live until you have confirmed calls are routing cleanly on VoIP. Cutting over before you have validated call quality is the single most common migration mistake. The steps below walk you through the full process in order.

What switching from landline to VoIP actually involves

Switching from a landline to VoIP is not a one-click event. It is a coordinated handoff between three parties: your current carrier (who controls your number), your new VoIP provider (who will host it), and your internal team (who needs endpoints configured before go-live).

The core sequence:

• Number porting — your existing number moves from the PSTN carrier to the VoIP platform. This is the long-pole step. It requires a Letter of Authorization (LOA), matching account details, and carrier cooperation. Porting typically takes 3–7 business days; providers like DialPhone offer same-day porting on eligible numbers.
• Account and DID setup — your VoIP provider provisions your account, assigns Direct Inward Dialing (DID) numbers if you are adding new lines, and configures your call routing, IVR, and voicemail before the port completes.
• Endpoint configuration — desk phones (SIP-based), softphone apps, and mobile apps need to be provisioned with the VoIP provider credentials before cutover day.
• Parallel run — both your landline and VoIP system stay live for 24–72 hours. Inbound calls test on VoIP while the landline remains the production line. Only after passing the parallel run do you formally decommission the landline.

Understanding the sequence matters because each step has a dependency: you cannot cut over before the port completes, and you should not decommission the landline before the parallel run passes.

Step 1: Audit your current lines and contracts

Before contacting a VoIP provider, document everything you currently have. Porting fails or stalls most often because the submitting account information does not exactly match the carrier’s records.

Gather the following before you start:

• Account name and service address on file with your current carrier — pull this from your bill, not from memory. The LOA must match character-for-character.
• Billing Telephone Number (BTN) — the main number on the account, which may differ from the numbers you actually use.
• All DIDs on the account — list every number you want to port and every number you plan to abandon.
• Contract end dates — early termination fees on copper lines can run several hundred dollars per line. If your contract expires within 30–60 days, timing the switch to avoid ETFs is worth the short delay.
• Fax lines — identify any dedicated fax numbers. Analog fax over VoIP requires either an ATA (analog telephone adapter) or a cloud fax service. See the FAQ below for the options.
• Alarm and POS lines — some alarm systems and older point-of-sale terminals are hardwired to POTS lines. These require separate handling and are out of scope for a standard VoIP migration.
• Elevator and emergency phones — buildings with elevator emergency phones, door intercoms, or fire-alarm dialers often have dedicated POTS lines. These must remain on POTS or receive an ATA solution. Do not port them as part of your primary migration.

Output: a spreadsheet with every number, its purpose, whether you are porting or abandoning it, and the contract status on each.

Step 2: Choose your VoIP provider (selection criteria)

Not all VoIP providers are equal on the dimensions that matter for a landline replacement. Evaluate on these criteria in priority order:

• Porting speed — the gap between “we support porting” and “same-day porting on eligible numbers” is measured in business disruption. DialPhone offers same-day porting on qualified numbers; most carriers quote 5–7 business days as standard.
• Setup fee — some providers charge $50–$300 per line in activation fees. DialPhone charges no setup fee. Confirm before signing.
• Geographic coverage — if your business has international offices or regularly calls international numbers, confirm the provider’s coverage. DialPhone covers 46 countries on all plans.
• SIP device compatibility — if you have existing SIP-compatible desk phones (Polycom, Yealink, Cisco 8800-series), confirm the provider supports BYO device. This avoids hardware replacement costs.
• Reliability and uptime SLA — look for 99.99% SLA with documented redundancy. Ask where failover routes if the primary data center goes down.
• Compliance — healthcare businesses need HIPAA BAA. Legal and financial businesses may need call recording retention guarantees. Confirm before signing.

Compare two or three providers against these criteria using the open VoIP pricing dataset and the business phone comparison. Do not choose on headline price alone — overage structures, porting speed, and international rates determine the real cost at scale.

Provider comparison for landline migration

Provider	Porting speed	Setup fee	Same-day porting	HIPAA BAA	International included
DialPhone	3–7 days (same-day eligible)	$0	Yes	All plans	46 countries
RingCentral	5–7 days	$0–$50/line	No	Enterprise only	UK, CA, AU
Nextiva	5–10 days	$0	No	Enterprise only	Limited
Dialpad	5–7 days	$0	No	No	UK, CA
8x8	5–15 days	$0–$100/site	No	X2+	47 countries
Ooma Office	7–14 days	$0	No	No	Limited
Vonage Business	5–10 days	$0	No	No	Limited

See the DialPhone business phone product page for full plan details including the no-setup-fee guarantee and 46-country coverage.

Step 3: Port your numbers (the 3-7 day process)

Number porting is the legally mandated transfer of your phone number from one carrier to another. The FCC requires carriers to release numbers on request; the process has defined steps but variable timelines depending on carrier cooperation.

What happens during a port:

1. You sign an LOA authorizing the new provider to act on your behalf with the losing carrier.
2. The new provider submits a port request with your account details.
3. The losing carrier validates the submitted information against their records. If anything mismatches — a character off in the account name, a wrong zip code — they reject the request and the clock resets.
4. The carrier approves the port and sets a Firm Order Commitment (FOC) date — the scheduled transfer time, typically 12:01 AM on the FOC date.
5. On the FOC date, the number transfers. Calls that hit your old carrier after the FOC route to the new provider.

To minimize delays:

• Pull the LOA details directly from your carrier bill, not from your internal contact list.
• Submit the port before noon on a business day — ports submitted late in the day are often queued to the next morning.
• Do not close or modify your current carrier account until the port completes — closing the account before the FOC date cancels the port.
• If your number is on a multi-line account, clarify with your new provider whether a partial port (moving some numbers but not all) is supported.
• For toll-free numbers, porting involves a separate process through the Responsible Organization (RESPORG) system. Toll-free ports typically take 3–5 business days via a different workflow than local number ports.

Port rejection reasons and fixes:

Rejection reason	Fix
Account name mismatch	Pull exact account name from carrier invoice
Address mismatch	Use billing address from invoice, not physical address
BTN mismatch	Confirm the BTN is the main number on the account, not a sub-number
Number not portable	Confirm number is not on a bundled contract with penalties
Carrier requires LOA signature from account holder	Ensure the right person signs — some carriers require the legal account owner

The number porting guide covers rejection reasons and how to resolve them. The number porting glossary entry defines the technical terms (LOA, BTN, FOC, RESPORG) you will encounter during the process.

Step 4: Set up endpoints (desk phones, softphones, mobile apps)

While the port is in progress — which gives you 3–7 business days — configure all your endpoints. Do not wait until port completion to start this step.

Desk phones (SIP hardware):

• SIP-compatible phones (Yealink T4x, Polycom VVX, Cisco 8800) can often be re-provisioned for a new VoIP provider without hardware replacement. You will need the SIP server address, SIP username, and authentication password from your new provider.
• Phones that are carrier-locked (common with some AT&T and Comcast Business desk phone rentals) may need to be unlocked or replaced.
• Auto-provisioning: most modern VoIP providers support zero-touch provisioning via a provisioning URL. Enter the URL in the phone’s admin interface and it pulls the correct SIP credentials automatically. This eliminates manual entry for each device.

Softphones:

• Most business VoIP providers offer a desktop softphone app (Windows/Mac) and a mobile app (iOS/Android). Install these on all devices before cutover so staff can make and receive calls the moment the port completes.
• Test outbound call quality on the softphone during the port window using a temporary DID your provider can assign for testing.

Mobile apps:

• Configure the VoIP mobile app with each user’s extension credentials. Enable push notifications so mobile users receive inbound calls even when the app is backgrounded.
• Test the mobile app on both Wi-Fi and cellular data. Some VoIP apps have codec settings that affect performance on LTE versus Wi-Fi — verify call quality under both conditions before cutover.

Headsets:

• USB and Bluetooth headsets paired to softphones should be tested for echo and latency before cutover. Most latency problems on VoIP calls are headset or network related, not carrier related.
• For large deployments (20+ seats), conduct a headset compatibility test with your VoIP provider before purchasing in bulk.

Step 5: Configure call flows and IVR before cutover

One step that migration guides underemphasize: configuring your call routing, IVR menus, ring groups, and voicemail before cutover — not after. If staff cannot reach the right person or IVR menus are wrong on cutover day, you burn goodwill with customers on the most visible day of the migration.

IVR and auto-attendant setup:

Map your current landline call routing before migration. Document every forwarding rule, ring group, and overflow destination. Recreate this in your VoIP platform during the port window. Then test every menu option with real phones before cutover.

Ring groups:

Ring groups (simultaneous ring or sequential ring to a set of extensions) are a standard VoIP feature. Configure these to match your current call distribution patterns. For businesses that used physical extensions on a multi-line desk phone, ring groups replicate the shared-line appearance.

Voicemail and voicemail-to-email:

Configure voicemail for every user and every ring group. Set up voicemail-to-email delivery. Test by leaving a voicemail on a temporary DID and confirming it arrives in email within 60 seconds.

After-hours routing:

VoIP platforms support time-based routing — calls after 6 PM or on weekends can route to a different destination (on-call number, voicemail, or answering service). Set this up during the port window and test it by simulating off-hours calls.

Step 6: Test before cutover (parallel run period)

A parallel run — keeping the landline live while actively testing the VoIP system — is the most important risk-reduction step in the migration. Skip it and you lose the ability to fall back if something goes wrong on cutover day.

How to run the parallel period:

• Ask your VoIP provider to assign temporary test DIDs before your port completes. Route real internal test calls through these DIDs.
• Call from a mobile phone into the temporary DIDs and verify: audio quality in both directions, hold music, IVR navigation, voicemail deposit, voicemail-to-email delivery.
• Make outbound calls from the VoIP system and verify Caller ID displays correctly.
• Test from multiple locations: the office, a remote worker’s home, a mobile hotspot. VoIP quality degrades under bad network conditions; find those conditions in the test period, not on cutover day.
• Verify fax-over-IP or cloud fax is working if you have fax lines in scope.
• Test the mobile app for inbound push notifications. Leave the app in the background and call the test DID — verify the ring notification arrives within 3 seconds.

Parallel run checklist:

Test item	Pass criteria	Notes
Inbound call quality	No echo, no jitter, MOS score 4.0+	Test from multiple locations
Outbound Caller ID	Shows correct business number	Not “Unknown” or temporary DID
IVR navigation	All menu options route correctly	Test every branch
Hold music	Plays without interruption	Check for silence gaps
Voicemail deposit	Message saved correctly	Test from external number
Voicemail-to-email	Email arrives within 60 seconds	Check spam folder
Mobile app inbound	Push notification within 3 seconds	Test with app backgrounded
Fax (if in scope)	Send and receive 10-page document	Check for page dropouts

If you find a problem during the parallel run, fix it before the port completes. The landline is your fallback; once you decommission it, the fallback is gone.

Step 7: Cut over and decommission landline

The FOC date is your cutover moment. On that date:

1. Confirm with your VoIP provider that the port completed successfully — they will notify you, but verify in the admin portal.
2. Make a test inbound call from a mobile phone to your ported number. Confirm it rings the correct destination on the VoIP system.
3. Make a test outbound call. Confirm Caller ID displays your ported number, not a temporary DID.
4. Confirm IVR routing, ring groups, and voicemail are functioning correctly on the ported number.
5. Notify staff the VoIP system is now live.

Only after this checklist passes should you contact your old carrier to cancel the landline service. Keep the final carrier bill for your records — you may need the account number and BTN if a porting dispute arises within 90 days.

Best day and time for cutover: Tuesday through Thursday, 10 AM to 12 PM local time. This window gives you maximum support availability from your VoIP provider if anything needs adjustment, and avoids weekend or late-Friday scenarios where support response is slower.

Review your DialPhone pricing plan to confirm your VoIP subscription covers your call volume and international destinations. Adjust the plan before the first full billing cycle if your usage during the parallel run suggests a different tier.

Common migration pitfalls and how to avoid them

Mismatched LOA details. The most common cause of port delays. The account name on the LOA must match the carrier’s record exactly — including punctuation and abbreviations. Pull it from the invoice, not from your CRM.

Porting a number on a bundled contract. Some carriers bundle internet, landline, and TV service. Porting the phone number away may trigger an unbundling clause and increase your internet bill. Confirm the contract structure before submitting the port.

Forgetting analog dependencies. Alarm systems, elevator phones, and some door entry systems run on POTS lines. These do not port to VoIP. Plan for analog workarounds — ATAs or dedicated POTS lines for those devices — before you cancel the main landline account.

Network not sized for VoIP. VoIP requires roughly 100 kbps per concurrent call. An office running 10 concurrent calls needs at least 1 Mbps headroom on a dedicated QoS-prioritized network segment. Check your router’s QoS settings and your ISP’s upload bandwidth before cutover. Jitter and packet loss — not download speed — are the usual culprits in poor VoIP quality.

Cutting over on a Friday. If anything goes wrong on cutover day, you want your VoIP provider’s support team immediately available. Do not schedule cutover for late Friday afternoon. Tuesday through Thursday mid-morning is the safest window.

Not updating published numbers. Your Google Business Profile, website, and printed materials all reference your old number. After the port completes, confirm the number is unchanged (porting preserves the number, so this should be automatic) and update any systems that cached the old carrier’s routing metadata.

Skipping QoS configuration. VoIP traffic needs router-level priority over general internet traffic. Without Quality of Service (QoS) rules, a large file upload can saturate upload bandwidth mid-call and cause audio dropout. Configure DSCP EF marking for voice traffic before cutover day.

Not testing remote workers separately. Office internet and home internet behave differently. A remote worker on a shared residential cable connection may experience jitter that office fiber does not. Test remote workers’ setups during the parallel run, not after cutover.

Per-Industry Migration Scenarios

Healthcare Practice (15 seats)

A 15-physician practice migrating from AT&T Business landlines to VoIP.

Specific considerations:

• HIPAA BAA required before any PHI-touching calls route through the new system
• Call recording required for audit trail (minimum 7-year retention in most states)
• Fax lines needed for referring provider communications — plan for cloud fax or ATA solution

Migration path:

1. Choose DialPhone Core (BAA included, call recording add-on at $8/seat/month)
2. Port all main lines. Keep 2 dedicated POTS fax lines on ATA until cloud fax is validated
3. Run 14-day parallel period including fax send/receive testing
4. Cutover main lines. Continue parallel fax test for additional 7 days before decommissioning POTS fax

3-year cost comparison:

• AT&T Business landlines (15 lines + features): $900–$1,350/month = $32,400–$48,600
• DialPhone Core + call recording (15 seats): ($24 + $8) × 15 = $480/month = $17,280
• Savings over 3 years: $15,120–$31,320

Law Firm (8 seats)

An 8-attorney firm on Comcast Business landlines.

Specific considerations:

• Attorney-client privilege requires secure call handling
• Call recording for client instruction documentation
• Comcast Business may have ETF if mid-contract — check before porting

Migration path:

1. Pull contract end date from Comcast portal. If within 45 days, wait for expiration to avoid ETF
2. Choose DialPhone Core with call recording add-on
3. Port during low-volume week (avoid tax season, major trial periods)
4. Verify CRM integration with practice management software before cutover

3-year savings at 8 seats vs Comcast Business:

• Comcast Business Phone (8 lines): $640–$960/month = $23,040–$34,560
• DialPhone Core + recording: ($24 + $8) × 8 = $256/month = $9,216
• Savings over 3 years: $13,824–$25,344

Retail Chain (3 locations, 30 total seats)

A retailer with locations in Chicago, Austin, and Denver.

Specific considerations:

• Each location needs local phone numbers for that city
• SMS required for customer notifications (appointment reminders, order ready alerts)
• Multi-location call routing from single admin portal

Migration path:

1. Port 3 main numbers (one per location) simultaneously. DialPhone supports parallel ports
2. Assign local DIDs for each city from DialPhone’s number inventory
3. Configure location-aware IVR: “Press 1 for Chicago, 2 for Austin, 3 for Denver”
4. Set up A2P 10DLC SMS registration ($4/month brand + $10/month campaign) before go-live

3-year cost at 30 seats:

• Legacy carrier 3-location setup: $1,500–$2,500/month = $54,000–$90,000
• DialPhone Core 30 seats: $720/month = $25,920
• Savings over 3 years: $28,080–$64,080

Remote-First Company (20 seats, no central office)

A fully distributed team where every employee works from home.

Specific considerations:

• No physical office — no central landline to port
• Each employee has a business number that needs to forward to their device
• E911 registration required for each home address

Migration path:

1. No porting of physical landlines — employees get new VoIP DIDs or port personal numbers if needed
2. Configure softphone apps for all 20 employees
3. Register E911 address for each employee
4. Enable call forwarding rules: business number → softphone app → mobile backup → voicemail

No ETF exposure, no landline infrastructure to decommission. Setup is faster than office-based migrations.

Cost comparison: monthly landline vs VoIP at the same call volume

Category	Traditional landline	DialPhone VoIP
Monthly line rental (per line)	$40–$65/line	Included in plan
Setup / activation	$50–$200/line	$0
Local calls	Included (usually)	Included
Long-distance (domestic)	$0.05–$0.10/min	Included
International (example: UK)	$0.15–$0.40/min	Included (46 countries)
Additional lines	$40–$65/line/mo	Low marginal cost
Mobile softphone	Not available	Included
IVR / auto-attendant	$20–$50/mo add-on	Included
Video conferencing	Not available	Included
CRM integration	Not available	Native (Salesforce, HubSpot)
AI call summaries	Not available	Included

A five-line business on traditional landlines pays $200–$325/month in line rental alone, before long-distance. The equivalent VoIP setup at DialPhone covers the same five users, IVR, voicemail-to-email, and 46-country international calling at a fraction of that cost with no setup fee.

Internet bandwidth requirements

VoIP quality depends directly on your internet connection. Before cutting over, verify your network meets these minimums.

Simultaneous calls	Minimum upload/download	Router recommendation
1–2	200 kbps	Any modern router with QoS
3–5	600 kbps	QoS-enabled router, VoIP VLAN recommended
6–10	1.5 Mbps	Dedicated QoS profile for voice traffic
11–20	3 Mbps	Business-grade router, DSCP marking
21–50	8 Mbps	Managed switch with traffic shaping
51–100	20 Mbps	Dedicated MPLS or SD-WAN for voice

The 100 kbps per concurrent call figure is for the voice stream only. Add headroom for general office traffic — a realistic target is 500 kbps per simultaneous call when accounting for network overhead and burst. Jitter and packet loss are more damaging than raw bandwidth: jitter above 30ms or packet loss above 1% produces audible audio degradation regardless of download speed. Test using a tool like PingPlotter before migration.

QoS configuration. Configure your router to tag VoIP packets with DSCP EF (Expedited Forwarding) marking, which instructs the router to prioritize voice packets over file downloads and video streams. Without QoS, a large file upload can saturate upload bandwidth mid-call and cause audio dropout. Most business-grade routers (Cisco Meraki, Ubiquiti, Netgear Orbi Pro) support DSCP marking in the admin UI.

Power outages and E911: what changes when you go VoIP

Traditional POTS landlines run on carrier-provided power — your desk phone works even during a power outage. VoIP does not. When your internet router loses power, calls cannot be made or received. Plan for this before cutover.

Power backup options:

• Uninterruptible Power Supply (UPS) for your internet router and any PoE switches powering desk phones. A $60–$120 UPS provides 1–4 hours of runtime.
• 4G/5G cellular failover router. Products like Cradlepoint or a cellular-enabled Meraki MX can automatically switch to cellular when the primary internet circuit goes down. VoIP calls route over cellular during the outage.
• Mobile app failover. Every employee with the VoIP mobile app can make and receive calls over their smartphone’s cellular data, bypassing the office internet entirely.

E911 accuracy. POTS 911 automatically dispatches to your registered address. VoIP E911 — called Enhanced 911 — works, but requires your address to be registered with the VoIP provider and kept current. If you move offices or have remote workers, each location must have an E911 address registered.

The FCC’s Kari’s Law (2020) requires multi-line phone systems to allow direct 911 dialing without a prefix. Confirm your VoIP provider complies. DialPhone supports direct 911 dialing and dynamic E911 location updates for remote workers via the mobile app. Register your address in the admin portal before go-live.

Early termination fees: check before you port

Porting your number away from a carrier counts as canceling the service. If you are mid-contract, your carrier may charge an early termination fee (ETF) that erases months of VoIP savings.

What ETFs look like in practice:

• Consumer-grade business lines (AT&T, Verizon): $0–$100 per line, often waived if contract has expired
• Multi-line business contracts (Comcast Business, Spectrum Business): $75–$300 per line, may require 30-day written notice
• Enterprise MPLS or managed voice contracts: ETFs can be calculated as remaining monthly fees × number of months left — potentially thousands of dollars

How to minimize ETF exposure:

1. Pull your contract end date from your carrier portal or your most recent bill. If you are within 30–60 days of expiration, wait.
2. Call your carrier and ask for the ETF amount before submitting the port. Get it in writing.
3. Some carriers waive ETFs if they have raised rates mid-contract without your consent — review your last two invoices for fee increases.
4. Negotiate: carriers often reduce or eliminate ETFs to prevent fully losing the account, especially if you offer to keep data or internet services with them.

DialPhone charges no ETF or early termination fee on any plan. If you find a lower-cost provider after 90 days, you can leave without a penalty.

VoIP hardware options

You do not need new hardware to switch to VoIP. But if you want physical phones, these are the options:

Hardware	Cost range	Best for
Softphone app (desktop + mobile)	$0	Remote teams, laptop-first offices
IP desk phone (entry)	$80–$150	Front desk, receptionist
IP desk phone (mid)	$150–$250	Sales teams, shared hot desks
Analog Telephone Adapter (ATA)	$40–$90	Keeps existing analog phones, fax lines
DECT wireless handset	$100–$250	Retail floors, warehouses, mobile staff
USB/Bluetooth headset	$30–$200	Agent desks, softphone-primary offices
Conference room IP phone	$200–$500	Meeting rooms with 4+ participants

Most modern IP desk phones (Yealink T4x series, Polycom VVX, Cisco 8800 series) are compatible with any SIP-standard VoIP provider. If you already own SIP-compatible phones, check with your new provider whether they support BYO device — DialPhone supports BYO SIP devices on all plans.

International call cost comparison

One of the strongest financial arguments for switching is international calling. Landline carriers charge per-minute rates set by PSTN interconnect agreements; VoIP providers often include international calling in plan bundles.

Destination	Landline rate (typical)	DialPhone VoIP
United Kingdom	$0.15–$0.40/min	Included (46 countries)
Canada	$0.05–$0.15/min	Included
Mexico	$0.10–$0.25/min	Included
Germany	$0.20–$0.45/min	Included
India	$0.25–$0.50/min	Included
Australia	$0.20–$0.40/min	Included

A business making 500 minutes of international calls per month to the UK at $0.25/min pays $125/month in long-distance charges alone. The same volume is included in DialPhone’s plan at no overage cost. Over 12 months, that is $1,500 in savings on international calling alone — before counting the line rental savings.

See the full per-country rate table in the open pricing dataset.

Related guides

• Best VoIP for Small Business 2026
• Business Phone AI Transcription
• Business Phone for Healthcare
• Cheap VoIP Service 2026
• Cloud Phone for Remote Teams
• DialPhone business phone
• DialPhone pricing

How We Tested

DialPhone re-verifies every comparison in this guide every 90 days. We pull pricing directly from each vendor’s public pricing page on the dates listed in the frontmatter. Where vendor pricing is gated behind a sales call, we mark “Contact sales” and use the lowest published equivalent from the past 12 months. Feature availability is checked against vendor documentation, not marketing pages. We do not accept paid placements or affiliate fees from any vendor — see our editorial standards.

What We Don’t Like

No platform is perfect, including DialPhone. Honest drawbacks based on user feedback and our own testing:

• Smaller integration catalog than RingCentral (~40 vs 200+). Niche vertical CRM integrations may require API work.
• Newer brand awareness. RingCentral and 8x8 have 15+ years of analyst coverage. Enterprise procurement reviews may take longer.
• Predictive dialer is an add-on ($15/user) for high-volume outbound teams running 200+ daily dials per rep.
• HIPAA BAA starts on Advanced tier ($34/user), not the $24 Core plan. Still cheaper than competitors that gate HIPAA behind enterprise-only contracts.

FAQ

Switching landline to VoIP: frequently asked questions

How long does porting take when switching from landline to VoIP? +

Standard number porting from a landline carrier to a VoIP provider takes 3–7 business days from the time the port request is submitted with a validated LOA. The variance depends on carrier cooperation and whether the initial submission has any mismatches that trigger a rejection and resubmission.

DialPhone offers same-day porting on eligible numbers — the eligibility check is part of the onboarding process. The most common cause of delays is a mismatch between the LOA details and the losing carrier's account records. Pull your account name and BTN from your carrier invoice, not from memory.

Can I keep my existing phone numbers when switching to VoIP? +

Yes. Number portability is a legal right in the US, UK, and most other markets. Your existing landline numbers — including local DIDs, toll-free numbers, and fax numbers — can be ported to a VoIP provider. The number itself does not change; only the underlying carrier routing changes.

The porting process requires a Letter of Authorization and matching account details. You keep the same number you have printed on business cards, your website, and your Google Business Profile. Do not cancel your current carrier account until the port completes, or the number may be released back into the numbering pool.

What about my fax line — can I port a fax number to VoIP? +

Yes, fax numbers can be ported to VoIP, but analog fax machines do not work natively over VoIP. You have two options. First, use an ATA (analog telephone adapter) — a device that converts the analog fax signal to a digital SIP signal — connected between your fax machine and the VoIP network. Quality can be inconsistent depending on fax speed and compression settings.

Second, switch to a cloud fax service (eFax, HelloFax, RingCentral Fax) and retire the hardware fax machine entirely. Cloud fax is the more reliable long-term option and costs $10–$25/month per line. If fax is business-critical, test the ATA or cloud fax solution during the parallel run period before decommissioning the POTS fax line.

Do I need new phones to switch to VoIP? +

Not necessarily. SIP-compatible desk phones — Yealink T4x, Polycom VVX, Cisco 8800-series, and similar models — can usually be re-provisioned for a new VoIP provider without replacement. You need the SIP server address and credentials from the new provider, and the phone must not be carrier-locked.

Carrier-locked phones (common with bundled hardware from AT&T Business and Comcast Business) may need to be unlocked or replaced. Most VoIP migrations also offer softphone apps — free desktop and mobile apps that turn a laptop or smartphone into a business phone — which eliminates desk phone requirements entirely for remote-first teams.

What internet speed do I need for VoIP? +

VoIP requires approximately 100 kbps upload and download bandwidth per concurrent call. An office handling 10 simultaneous calls needs at least 1 Mbps dedicated to VoIP traffic, with Quality of Service (QoS) configured on your router to prioritize voice packets over general internet traffic.

Download speed is rarely the constraint — jitter and packet loss are the primary causes of poor VoIP call quality. Test your connection at a site like PingPlotter before migration to identify any jitter issues. Most business broadband connections of 25 Mbps or higher handle typical VoIP call volumes without issues.

Is there a setup fee to switch to VoIP with DialPhone? +

DialPhone charges no setup fee. Account provisioning, number porting, and endpoint configuration support are included in the plan at no additional cost. Some competitors charge $50–$300 per line in activation or onboarding fees that only appear in the final order form, not on the public pricing page. Always confirm setup fee structure in writing before signing. The no-setup-fee policy applies to all DialPhone plans; see the pricing page for plan details.

Can I switch just some of my lines to VoIP and keep others on landline? +

Yes. Partial migrations — where some lines move to VoIP and others remain on POTS — are common during a phased rollout. You can port specific DIDs from your account while leaving others in place, as long as your current carrier supports partial porting (most do). A phased approach is useful for businesses with analog dependencies (alarms, elevator phones, POS terminals) that are not ready to move to VoIP simultaneously. Run the VoIP lines in parallel with the remaining landlines until you have confidence in call quality, then port the remaining lines in a second wave.

What happens if something goes wrong on cutover day? +

If the port fails or call quality is unacceptable on cutover day, your landline is still live if you have not cancelled it yet — this is why the parallel run period is critical. Do not cancel your landline until you have verified the ported number is working correctly on VoIP. If the FOC date arrives and the port has not completed, your old carrier continues handling calls. Contact your VoIP provider's support team immediately — they can contact the losing carrier to expedite. Most providers have 24/7 migration support; confirm this before signing.

How much does switching from landline to VoIP save? +

Savings depend on seat count, current carrier rates, and international calling volume. A typical 25-seat SMB paying $50–$65/line/month on a traditional landline spends $18,000–$23,400/year. The same team on DialPhone Core at $24/seat pays $7,200/year — saving $10,800–$16,200 annually. Over 3 years, that is $32,400–$48,600 in savings. Add international calling savings if your team calls UK, Canada, or Australia, where landline per-minute rates of $0.15–$0.40/min compare to VoIP's included unlimited calling on those routes.

What should I tell my staff before the migration? +

Brief staff at least one week before cutover day. Explain: (1) the phone number stays the same after porting, so customers will reach them at the same number; (2) they need to install the softphone or mobile app and test it before cutover day; (3) the transition date and time so they are not surprised; (4) who to call internally if they have a call quality issue in the first 48 hours. A brief 15-minute training on the new admin portal and voicemail access eliminates most support requests during the first week.

Related reading

• Best AI business phone systems 2026 — side-by-side comparison of VoIP platforms for businesses of all sizes
• DialPhone business phone — full plan details, same-day porting, no setup fee, 46-country coverage
• VoIP vs landline: full comparison — concept-level comparison of the two technologies for businesses still evaluating
• Number porting guide — deep dive on LOA requirements, rejection reasons, and how to fix them
• Number porting glossary — definitions for LOA, BTN, FOC, RESPORG, and other porting terms
• DialPhone pricing — plan options, included minutes, and international rate tables
• Open VoIP pricing dataset — 13-provider transparency dataset with per-country international rates

---

This guide reflects standard number porting timelines and VoIP migration practices as of May 2026. Porting timelines vary by carrier and country. Confirm current porting eligibility and setup fee terms directly with your provider before initiating a migration. Factual corrections: [email protected].