The single most expensive thing in a POTS migration is the line you forgot to migrate. Below is the field-tested audit process we run on every property before we quote a replacement.
Step 1 — Pull 12 months of carrier invoices
Get bills from every voice carrier the property has used in the last year — primary ILEC plus any inherited from an acquisition or prior management company. Build a spreadsheet with one row per BTN (billing telephone number).
Step 2 — Walk the building
Bills miss lines. In a typical commercial building you will find:
- Fire alarm communicator (often two lines: primary + secondary)
- Elevator phone in every car (including freight)
- Area-of-rescue stations on each floor
- Burglar / intrusion panel
- Sprinkler tamper / water-flow alarm
- Gate or garage door intercom
- Pool-area emergency phone
- Pharmacy or lab modem
- Fax in accounting, HR, shipping
- POS / credit-card backup line
- Generator monitoring modem
Step 3 — Classify by criticality
Tag each line:
- Life-safety (fire, elevator, area-of-rescue): LTE-based replacement, battery backup, listed device. See fire and elevator.
- Monitored alarm: LTE replacement, often dual-path. See security alarm.
- Revenue-impacting (POS, fax): LTE or SIP. See fax & POS.
- Office voice: SIP / hosted PBX.
Step 4 — Confirm each line is actually in use
Call every BTN from a cell phone. Lines that ring nowhere or hit a fast-busy can usually be canceled outright — that is immediate savings.
Step 5 — Document monthly spend per line
Total monthly cost ÷ active lines = current per-line cost. Anything above $75/month is a strong replacement candidate today.
Step 6 — Build a migration order
Migrate in this sequence: highest-cost lines first → life-safety lines next → everything else. This frees up budget early and keeps compliance covered.
We do this for free on portfolios > 5 sites
Send us your address list and we'll return an audit and per-line quote. Request a portfolio audit.