Providers

Start with SIP registration

This phone lives behind your router with no port forwarding. It opens the connection outward and calls arrive back down that same pipe. The first question to ask is:

Does the provider accept an outbound SIP registration?

Registration makes a provider a candidate. You still need to verify incoming calls, two-way audio, keypad tones, caller ID and emergency routing with your configuration. Providers that require unsolicited inbound connections to a public IP need a different network setup from the one documented here.

Nobody is paying for this placement

No provider pays for placement, and none of these links earns a commission. They carry utm_ parameters identifying Call Me Maybe as the referring site to the provider. Those tags alone do not tell us who clicked or signed up.

Prices below were checked on October 5, 2026. They are USD examples for US local voice service, before taxes and regulatory surcharges. Starting rates vary by destination and number availability; follow the sources for a quote. Hardware, internet, electricity, messaging and optional services are extra.

What a light-use month might cost

One number, one phone, 100 incoming minutes and100 outgoing, at advertised starting rates rather than destination quotes. Hardware is a Raspberry Pi 5 and one Grandstream WP826. Tin Can is one phone on Party Line, since a phone that only calls other Tin Cans is a different purchase.

Year 1 is hardware, the one-time fees each provider lists and twelve months of service, less Tin Can’s free first month; year 2 is service alone. Taxes, surcharges and a prepaid deposit are not in it. The deposit funds future use and is separate from the monthly figure.

Our starting recommendation: VoIP.ms for the documented Call Me Maybe setup. Compare Callcentric for bundled minutes, and Telnyx or Flowroute if their carrier tools suit you. A lower advertised minute rate is only one part of the decision.

This is a supplementary home phone. Configure and verify the registered emergency address and routing using the provider’s testing procedure. Power and internet outages can interrupt service; keep another way to reach emergency services.

What a house costs, by the year

The light-use month above is one number and one phone. A house with children on the phone looks more like the standard issue below. Change any of it; the table follows.

• Handsets: 3 by default, one in the kitchen for the grown-ups and one for each of two kids. Each is a Grandstream WP826 at $110, on a Raspberry Pi 5 at $80: the pair the project is tested against, not the cheapest. Pick others from the hardware list below; every brain and every standalone handset on it is offered.
• Minutes: two kids at 30 minutes a week each is about 260 a month, which is the default; the kitchen phone’s calls are on top. Enter the house total or an average per handset. Half are placed from the house and half rung in.
• One house number with E911, at each provider’s advertised US starting rates.

Tin Can is in the table because it is the other answer to the same question: a phone for a kid who does not have a smartphone. It is not a SIP provider. It is a phone with the service built in, so its row counts one Tin Can per handset at $100 each. Calls between Tin Cans are free. Calling anyone else needs a Party Line plan at $9.99 a month for each Tin Can with its own number, first month free; Tin Cans linked to one shared number need one plan between them, and all ring at once. Two questions decide most of the Tin Can row.

Over four years Tin Can costs $1127.42 more than Telnyx at these settings. Year 1 is hardware, the one-time fees each provider lists and twelve months of service, less Tin Can’s free first month. Year 2 is service alone, and so is each year after it.

Party Line is a flat fee. It is needed for the first minute of outside chat and costs the same for the last, so the slider only changes the Tin Can row at its far right, where every call is to another Tin Can. Spread over the outside minutes at this setting it comes to about $0.23 for each minute of outside chat.

Sharing a number cuts it to one plan. Tin Can can link several phones to one number on a single Party Line, $9.99 a month; choose “one shared” above to price it. Every call then rings every Tin Can, and they share one contact list and one voicemail, which is the part a Call Me Maybe house routes with ladders and extensions instead.

The friends who do have Tin Cans cost a Call Me Maybe house the same carrier minute as anyone else, and the call only connects if that family has Party Line: the free plan reaches other Tin Cans only. Slide all the way to “all Tin Can calls” and the Tin Can row has no monthly cost, and no way to call a house like this one.

Left out on both sides: tax and surcharges, a prepaid deposit, Wi-Fi, electricity, a power supply, storage and case for the brain, PoE or a power adapter for a desk phone, and your time. Only VoIP.ms, Telnyx, Callcentric are costed; Flowroute’s recurring number charge should be confirmed in the portal first.

Cost is a tiebreaker. This is the argument.

A phone system in the house is a different thing from a phone with a plan. The rows below are what a Call Me Maybe house does with the handsets it already has, next to what Tin Can’s own pages say its phone does. Where those pages say nothing, the cell says no; tell us if that is wrong. A row marked planned is on the roadmap, not in the binary, and says so rather than counting it.

Tin Can column from product and plans, can 2 can vs party line, one number per device, or shared. No Tin Can was used for this page.

Evaluating one that is not listed

The list does not need to be exhaustive to be useful. Ask a prospective provider these, in order:

1. Registration or IP auth? If they cannot do registration, stop here.
2. Sub-accounts? The credential on the Pi should never be your portal login — if the Pi is compromised, you want to revoke one thing rather than everything.
3. Several numbers on one registration? This is what makes a second line cheap instead of a second trunk.
4. Prepaid or postpaid? Prepaid can stop service when the balance reaches zero. A phone that simply stops ringing is indistinguishable from a quiet week. If prepaid, set up a balance alert on day one.
5. E911? Confirm availability, address and charges. A house phone that cannot reach emergency services is a thing the people in that house should know about.

Found one that works? The runbook has a worked configuration, and a pull request adding a provider block is genuinely welcome — but please verify it against a live trunk first. A wrong example costs more than a missing one.