Show HN: Dtmf.io – virtual phone numbers from 50 countries, and SIMs in the UK
1–10 of 28 posts
Re: Show HN: Dtmf.io – virtual phone numbers from 50 countries, and SIMs in the UK
#2The product offering of a per-hour mobile number to receive SMS is great, I've not seen this elsewhere.
Re: Show HN: Dtmf.io – virtual phone numbers from 50 countries, and SIMs in the UK
#3How do you get the numbers? (Or, bluntly, how do I distinguish this from a productized SIM-swapping operation? Is it significantly cheaper than that would be? Or significantly more expensive?)
Re: Show HN: Dtmf.io – virtual phone numbers from 50 countries, and SIMs in the UK
#4The monthly charges seem reasonable. I didn't see any info on the site about inbound call pricing, service and limitations. Specifically:
- per-minute charges?
- # simultaneous channels?
- delivery options? (e.g. can I register a SIP device on your gateway, or can you accept a SIP URI)
Re: Show HN: Dtmf.io – virtual phone numbers from 50 countries, and SIMs in the UK
#5The monthly charges seem reasonable. I didn't see any info on the site about inbound call pricing, service and limitations. Specifically: - per-minute charges? - # simultaneous channels? - delivery options? (e.g. can I register a SIP device on your gateway, or can you accept a SIP URI)
Thanks - we'll add this information.
The per-minute charges are fixed for a given number type for inbound calls. They're cheapest for landline numbers (e.g. just under EUR 0.01 per minute for a UK landline), very slightly more expensive for mobile numbers, and quite a lot more expensive for toll-free numbers (since you're paying the cost for the caller). For outbound calls, it depends where you're calling. There are volume discounts available.
We guarantee one simultaneous channel per phone number for Basic accounts. For Pro accounts ($10/month) we guarantee an additional 8 simultaneous channels which can be used across any of the phone numbers as demand requires. Those are guarantees and our system will often allow bursting above them if capacity allows.
For Business accounts (negotiated minimum spend) we can negotiate any number of simultaneous channels.
Pro & Business accounts have SIP support, both registration and directing inbound calls to a SIP URI.
Re: Show HN: Dtmf.io – virtual phone numbers from 50 countries, and SIMs in the UK
#6How do you get the numbers? (Or, bluntly, how do I distinguish this from a productized SIM-swapping operation? Is it significantly cheaper than that would be? Or significantly more expensive?)
The virtual numbers come from a few different suppliers, one being Twilio for example.
The physical SIM numbers are infrastructure that we built, using racks of GSM modems, SIM card switching devices, and our own software to manage everything. The SIM card switching devices reduce maintenance requirements since when a customer no longer needs a SIM, we can electronically switch the modem to a new SIM without needing to visit the datacentre. We just have to go every so often to replace the used SIMs before the pool runs low.
Re: Show HN: Dtmf.io – virtual phone numbers from 50 countries, and SIMs in the UK
#7How do you get the numbers? (Or, bluntly, how do I distinguish this from a productized SIM-swapping operation? Is it significantly cheaper than that would be? Or significantly more expensive?)
The virtual numbers come from a few different suppliers, one being Twilio for example. The physical SIM numbers are infrastructure that we built, using racks of GSM modems, SIM card switching devices, and our own software to manage everything. The SIM card switching devices reduce maintenance requirements since when a customer no longer needs a SIM, we can electronically switch the modem to a new SIM without needing…
Wouldn't number verification systems (for example, Facebook) eventually start blacklisting your numbers? I have seen this happen with VOIP numbers. Do you have a plan to tackle this?
Re: Show HN: Dtmf.io – virtual phone numbers from 50 countries, and SIMs in the UK
#8Earlier quoted context omitted.
The virtual numbers come from a few different suppliers, one being Twilio for example. The physical SIM numbers are infrastructure that we built, using racks of GSM modems, SIM card switching devices, and our own software to manage everything. The SIM card switching devices reduce maintenance requirements since when a customer no longer needs a SIM, we can electronically switch the modem to a new SIM without needing…
Wouldn't number verification systems (for example, Facebook) eventually start blacklisting your numbers? I have seen this happen with VOIP numbers. Do you have a plan to tackle this?
The physical SIM numbers are SIMs from major UK providers, and are never re-used (for clarity: if you buy a SIM number, you get a SIM that has never been used by anyone else, and it will never be used by anyone else after you).
From the perspective of a number verification system (or anything else sending an SMS to them), they are completely indistinguishable from a mobile phone and prepaid SIM, since that is what they are.
The virtual numbers, while also never re-used, are often blacklisted by services that do SMS verification due to coming from a range designated as "VoIP" or "virtual", and we explicitly disrecommend their use for verification, although some people do use them with varying amounts of success since they are cheaper than the SIM numbers.
Re: Show HN: Dtmf.io – virtual phone numbers from 50 countries, and SIMs in the UK
#9Earlier quoted context omitted.
Wouldn't number verification systems (for example, Facebook) eventually start blacklisting your numbers? I have seen this happen with VOIP numbers. Do you have a plan to tackle this?
The physical SIM numbers are SIMs from major UK providers, and are never re-used (for clarity: if you buy a SIM number, you get a SIM that has never been used by anyone else, and it will never be used by anyone else after you). From the perspective of a number verification system (or anything else sending an SMS to them), they are completely indistinguishable from a mobile phone and prepaid SIM, since that is what th…
Great to know that the SIM numbers are not re-used across customers. Would this also mean that I have no way to re-claim a previously owned number?
Re: Show HN: Dtmf.io – virtual phone numbers from 50 countries, and SIMs in the UK
#10Earlier quoted context omitted.
The physical SIM numbers are SIMs from major UK providers, and are never re-used (for clarity: if you buy a SIM number, you get a SIM that has never been used by anyone else, and it will never be used by anyone else after you). From the perspective of a number verification system (or anything else sending an SMS to them), they are completely indistinguishable from a mobile phone and prepaid SIM, since that is what th…
Great to know that the SIM numbers are not re-used across customers. Would this also mean that I have no way to re-claim a previously owned number?
You can keep a phone number as long as you like. If you accidentally delete it or allow it to expire, then we can probably, on a best-effort basis, recover the phone number for you if you alert us quickly after you make the mistake. Once we have done a resupply of the SIM card pool the SIMs that have been used and are no longer in use are destroyed, at which point we can't get the number back for you.