How to Replace Your Landline with VoIP: A Practical Migration Guide

Landlines served businesses well for over a century, but the era of copper-wire phone systems is ending. Carriers are sunsetting PSTN infrastructure, maintenance costs are rising, and features that modern businesses need — remote work support, CRM integration, call analytics — simply are not available on a landline. Switching to VoIP is not just about saving money (though the savings are substantial). It is about getting a phone system that works the way your business works today. This guide gives you a clear, step-by-step path from landline to VoIP with zero disruption to your callers.

Before you can replace your landline, you need to understand what you have. Document the following: Phone numbers: List every number — main line, direct inward dial (DID) numbers, toll-free numbers, fax lines, and any hunt group or rollover numbers. Lines and extensions: How many physical phone lines come into your building? How many extensions are connected to your on-premises PBX? Call flow: How are calls routed today? Is there an auto-attendant, ring group, or receptionist who manually transfers calls? Features in use: Voicemail, call forwarding, conference calling, intercom, paging? Note which features your team relies on daily. Monthly cost: Gather your phone bills for the last 3 months. Include line charges, long-distance fees, PBX maintenance contracts, and any add-on feature costs. This audit gives you a baseline to compare against VoIP providers and ensures nothing is missed during migration.

VoIP requires a reliable broadband connection. Verify the following: Bandwidth: Each concurrent call uses about 100 kbps upload and download. If your office has 10 simultaneous calls at peak, you need at least 1 Mbps dedicated to voice — but more headroom is better. Latency: Under 150 ms for clear conversation. Jitter: Under 30 ms to prevent audio distortion. Packet loss: Under 1 % for consistent quality. Run a VoIP readiness test (your VoIP provider can supply one) to measure these metrics. If results are borderline, consider upgrading your internet plan or enabling Quality of Service (QoS) on your router to prioritize voice packets.

Evaluate providers based on the features and routing you documented in Step 1. Key criteria: • Does the plan include all the features you need without expensive add-ons? • Does the provider support number porting for all your existing numbers? • Is there a mobile and desktop app for remote and hybrid workers? • Is the admin portal user-friendly enough for non-technical staff? • Does the provider offer onboarding support and guided setup? • What is the uptime SLA and where are the data centers located? ON VoIP includes unlimited domestic calling, 50+ features, number porting, mobile and desktop apps, and guided onboarding — all in a single subscription with no hidden charges.

Migration is a perfect opportunity to modernize how calls are handled. Design your new call flow before configuring anything: Main line: Should it ring a receptionist, go to an auto-attendant, or both based on time of day? Departments: Create ring groups for Sales, Support, Billing, etc. Decide whether phones should ring simultaneously (ring-all) or in sequence (round-robin). After hours: Set up an after-hours auto-attendant with voicemail, on-call forwarding, or a call queue. Remote workers: Assign extensions to softphone apps so remote employees are part of the same phone system. Fax: Decide whether to keep a physical fax machine (via ATA) or switch to eFax. Document the call flow as a simple diagram — it makes configuration faster and ensures nothing is overlooked.

Decide which employees need desk phones vs. softphones: Desk phones: Ideal for employees who handle high call volumes — receptionists, salespeople, support agents. Order IP phones that your VoIP provider supports for auto-provisioning. Softphones: Free desktop and mobile apps that turn a computer or smartphone into a full business phone. Best for remote workers, executives, and employees who make fewer calls. Conference phones: One per meeting room, sized for the room capacity. ATAs (Analog Telephone Adapters): If you need to keep analog fax machines, door phones, or paging systems connected. Most providers ship pre-configured phones — just plug them into your network and they register automatically. No manual programming needed.

Log into your provider's admin portal and set up: • Company profile: name, address, time zone, default caller ID. • Extensions: create one for each user with name, email, voicemail. • Auto-attendant: upload greeting, map key presses to departments. • Ring groups: group extensions by team. • Call queues: for high-volume departments like support. • Business hours schedule: define when your office is open and configure after-hours routing. • Voicemail: greetings, voicemail-to-email, transcription settings. Test each component with temporary numbers supplied by your provider while you wait for your landline numbers to port.

Submit number porting requests for all your existing landline numbers. You will need: • A recent phone bill from your current provider • Account number and any PINs • A signed Letter of Authorization (LOA) Critical: do not cancel your landline service before the port completes. Your old service stays active until the port goes live. Prematurely disconnecting your line can cause the number to be lost. Ports typically complete in 7–14 business days. Your VoIP provider manages the process and notifies you of the scheduled cutover date.

Before flipping the switch for your team, run a comprehensive test: • Call your main number and test every auto-attendant option. • Call each department ring group and verify all phones ring. • Test voicemail delivery and transcription. • Make outbound calls from desk phones and softphones — verify caller ID. • Test call recording, transfer, and park. • Simulate an internet outage and confirm failover routing works. Once everything passes, communicate the go-live date to your team. If numbers are already ported, the transition is transparent to callers. Schedule a 15–20 minute training session to walk your team through: • Answering, transferring, and parking calls • Using the company directory • Setting up voicemail and call forwarding • Using the mobile app

After confirming that all ported numbers are working correctly on your VoIP system, contact your old landline provider to formally close the account. Request: • Final bill with no early termination fees (porting typically satisfies contract terms, but verify) • Return instructions for any carrier-owned equipment (modems, PBX cards) • Written confirmation of account closure Keep your final landline bill on file for 12 months in case of any billing disputes.

Replacing your landline with VoIP is one of the smartest infrastructure decisions a business can make. The process is straightforward — audit, prepare, configure, port, test, go live — and the payoff is immediate: lower costs, better features, and a phone system that supports the way your team actually works. ON VoIP handles the heavy lifting. Our onboarding team guides you through every step — from network assessment to number porting to go-live testing — so you can make the switch with confidence and zero downtime.