You just became the IT Director. The phone system is 12 years old, the maintenance contract costs more than the system is worth, and the CFO wants a plan. Here is the exact 90-day roadmap I have used for 40+ enterprise migrations.
Days 1-15: Discovery and Business Case
Week 1: Gather Data
| What to Collect | Where to Find It | Why You Need It |
|---|---|---|
| Current monthly telecom invoices | Finance/AP department | Calculate current cost |
| Number of active extensions | PBX admin portal | Size the new system |
| Peak concurrent calls | CDR reports or PBX dashboard | Determine bandwidth needs |
| Current features in use | Interview department heads | Ensure feature parity |
| Contract end dates | Procurement/legal | Know your exit timeline |
| Network topology | Network team | Plan QoS and VLAN |
Week 2: Build the Business Case
The CFO needs one page:
CURRENT STATE:
Monthly cost: £X
Per-user cost: £Y
Features paying extra for: [list]
Contract ends: [date]
Maintenance renewal: [date] at [% increase]
PROPOSED STATE:
Monthly cost: £A (B% reduction)
Per-user cost: £C
Features included: everything
Contract: month-to-month
FINANCIAL IMPACT:
Monthly savings: £D
Annual savings: £E
One-time costs: £F (phones + implementation)
Payback period: G months
3-year net savings: £H
If the payback period is under 6 months (it usually is), the CFO will approve.
Days 15-30: Vendor Selection
The 3-Provider Trial
Get trial accounts from your top 3 providers. Run this test:
| Test | Duration | What to Measure |
|---|---|---|
| Call quality | 5 days, 20 calls/day | MOS score average |
| Mobile app | 3 days exclusive use | Notification reliability |
| Support | 3 calls at different times | Wait time + answer quality |
| Admin portal | 1 hour with office manager | Task completion time |
| CRM integration | 1 day | Auto-logging accuracy |
Score each provider 1-5 per test. Winner gets the contract.
Days 30-60: Network Preparation and Configuration
Week 5-6: Network
- [ ] Run bandwidth/jitter/latency test at all sites during peak hours
- [ ] Configure QoS (DSCP EF for voice, CS3 for SIP)
- [ ] Set up voice VLAN separate from data
- [ ] Disable SIP ALG on all routers/firewalls
- [ ] Open firewall ports: 5061/TCP, 10000-20000/UDP, 3478/UDP
- [ ] Test WiFi coverage for softphone users
Week 7-8: System Configuration
- [ ] Auto-attendant: record greeting, configure menu
- [ ] Ring groups: replicate current call flow
- [ ] Call recording: enable per company policy
- [ ] CRM integration: connect and test
- [ ] Mobile apps: deploy to pilot group
- [ ] Voicemail: configure greetings and email delivery
- [ ] E911/emergency calling: register all locations
Days 60-75: Pilot
10 Users for 2 Weeks
Select 10 users from different departments. Give them the new system on temporary numbers. They use both systems for 2 weeks.
Track:
- Call quality complaints (target: 0)
- Feature gaps ("I used to be able to...")
- Training questions (document for full rollout)
- Mobile app reliability (notification success rate)
Fix every issue found during pilot before proceeding.
Days 75-90: Full Rollout
Week 11: Training
- 30-minute department sessions (not company-wide — too impersonal)
- Quick reference cards distributed
- Floor walkers scheduled for days 1-3 post-go-live
Week 12: Number Porting and Go-Live
- Submit port request (Tuesday — never Friday)
- Port completes in 5-10 business days
- Old system kept as reference for 14 days
- Decommission old system at day 14
Week 13: Stabilisation
- Daily check-in with department heads
- Review call quality analytics
- Address any remaining training gaps
- Collect employee satisfaction survey
The Success Metrics
Present these to the CFO at day 90:
| Metric | Target | How to Measure |
|---|---|---|
| Monthly cost reduction | 40-70% | Compare invoices |
| Call quality (MOS) | > 4.0 | VoIP analytics dashboard |
| Employee satisfaction | > 4.0/5 | Survey |
| Missed call rate | < 5% | VoIP analytics |
| Mobile app adoption | > 60% | VoIP analytics |
| Help desk tickets (phone-related) | < 5/week | Help desk system |
DialPhone provides a dedicated migration specialist who partners with your IT team through all 90 days — from business case preparation to post-go-live stabilisation. The specialist has done this 200+ times. Your first time doing it benefits from their experience.
