Blog · Professional services
The solo founder's phone problem
One mobile, four kinds of caller, and no way of knowing which is which until you've already picked up.
By the CosVoice team · · 5 minute read
One Wednesday, one mobile
9:12am, unknown number: a customer whose order hasn't shipped. 10:30, the packaging supplier returning Monday's call, while you're on a video call. 11:05, a recruiter with a wonderful fractional CFO. 1:40pm, an angel you met at a demo night, who said she'd ring. 3:15, the payment processor's risk team. 4:50, unknown, no message.
That's the solo founder's phone problem in a single day. Everything lands on the same mobile with the same ring, and the two calls that mattered (the angel, the processor) looked exactly like the ones that didn't. The fix is a separate startup phone number that answers for the company, takes the details and sorts the callers. Your mobile goes back to being yours. The rest of this is about what each kind of caller should get.
Investors get a warm answer and a fast callback
An investor who rings instead of emailing has something they'd prefer to say out loud. You want that call. What you don't want is to miss it because it came from a number you didn't recognize, wedged between two sales calls.
So investors go on a short list. On our line, contacts can be marked as approved or VIP. A VIP caller is recognized, treated warmly, given time, and told you'll see this right away. The written summary reaches you as soon as the call ends, and you ring back. To be plain, that's a callback. The line can't put a caller through to your mobile, VIP or not. We cover the setup in approved, VIP and blocked callers.
It doesn't pitch. It doesn't quote your revenue or discuss the round. Anything it's asked about the business that you haven't written down gets "I'll have Graham come back to you on that", which is what a sensible chief of staff would say.
Customers want an answer, or a time
Early customers phone more than you'd expect, especially if you sell to small businesses. They ring about an order, a login, an invoice, a delivery window.
A line briefed with your basics can answer the basics: opening hours, the returns policy, where to send a support email, the prices on your public page. For everything else it takes the order number or account email, the problem in the customer's words, how urgent it is, and the best number. Then it tells them when they'll hear back.
That last part matters more than founders think. A customer who's told "by noon tomorrow" and hears at eleven is happier than one who got you live and distracted, promising to look into it.
Vendors are where the phone tag lives
You ring the packaging supplier, they're out. They ring back while you're in a meeting. You ring back, they're at lunch. Three days to get a price on five hundred boxes.
Here the line does two jobs. When the supplier rings back, it has the conversation you would have had: the price, what's included, the minimum order, the lead time, how long the quote holds. And it can place the call in the first place. Ask it to ring the supplier about the quote, or to wait on hold with the shipping company's business desk and put you through once a person answers. It reports back in writing either way.
It won't agree to a charge or read out a card number. If the supplier wants a deposit, that comes back to you as a decision.
Recruiters and cold callers get a polite wall
Once your company is in a database somewhere, the calls start. Recruiters, outsourced development shops, lead lists, office space. None of them are villains and a few are useful. None should cost you a context switch at 11am.
The line takes a name, a company and one sentence on what they're offering, and suggests email. You skim the summaries on Friday afternoon. If one keeps ringing, block the number.
Your company number belongs everywhere your mobile is now
The website footer. The invoice template. The app store listing, the domain registration, supplier account forms, your email signature. Pick a number in the area code where your customers are, if that's different from where you live.
You can also forward the calls you miss on your mobile to the line, which covers everyone who already has your number. The carrier codes are on the voicemail page. And if you already work with an AI assistant, Grok, ChatGPT or Claude for instance, you can connect it, so the assistant you talk to all day is the one reading the call summaries. How it works has the steps.
Some calls should stay on your own phone
Not everything should go through a line, ours or anyone's.
Keep the conversations where your voice is the point. A term sheet discussion. Telling a candidate they've got the job, or that they haven't. The call to an upset customer once you've read what went wrong. Your co-founder search. Your bank's fraud team, who need to verify you and nobody else. Anything that ends in a signature.
A useful test: if a good chief of staff sat next to you, would you hand them this call? If yes, the line can take it. If you'd say "no, I'd better do that one", you're right. And your mother should always have your real number.
Common questions
Does a startup need a phone number at all?
If you sell to businesses, take payments or deal with suppliers, yes. Banks, processors and vendors all ask for one, and some customers will only ring. The question is whether that number should be your personal mobile, and we'd say no.
Can the line make us sound like a bigger company?
It answers in your company's name and sounds professional, but it doesn't pretend. It introduces itself as an assistant and says it's an AI whenever anyone asks. We wouldn't invent departments you don't have.
Can I add a second line later for support or a co-founder?
Yes. One account can hold as many lines as you need. Each line has its own number, its own email address and its own plan.
What does it cost?
Plans start from $29 a month. The pricing page lists what each plan includes.
Read next: What is an AI chief of staff? · Keep your mobile number private · Let an AI wait on hold for you
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