Call Forwarding to Answering Service: The Codes, the Timer and the 11 PM Test
You signed with an answering service on Friday. Monday at 7:50 AM the first call of the week rings your office phone nine times and drops into a voicemail box nobody has checked since spring. The service was ready. The phone was never pointed at it.
Call forwarding to answering service coverage is a ten-minute job, and it’s where most setups quietly break. The wrong code on the wrong phone, a no-answer timer that fires before anyone can reach the handset, or a forward that works from your cell but not from a customer’s phone.
This guide covers the three decisions that matter: which kind of forwarding you want, which code your phone actually accepts, and how to prove it works before a real customer finds out it doesn’t.
Pick the forwarding type before you dial anything
Every phone system gives you some version of these four options. Choose first, because each one uses a different code.
| Type | What happens | Who it fits |
|---|---|---|
| Unconditional (always-on) | Every call goes straight to the service. Your phone never rings. | Owner-operators on a roof all day; nights if you flip it on and off |
| No-answer | Your line rings for a set time, then rolls over | Shops with someone in the office most of the day |
| Busy | Rolls over only when the line is already in use | Single-line offices that miss calls during calls |
| Scheduled (time-of-day) | Forwarding turns on and off by clock | Nights and weekends only; mostly a VoIP portal setting |
My take: most shops with a front desk want no-answer plus busy together. You keep every call your people can grab and only hand off the overflow. Unconditional forwarding during business hours pays a service to answer calls your office manager was sitting right there for. We walked through the same trade-off for plumbers in the answering service for plumbing companies guide.
Scheduled forwarding is the one to be careful with. It only works if the schedule lives in the phone system. If “scheduled” means someone dials a code at 5 PM, it’ll get missed on the day a crew comes back late.
Call forwarding to answering service codes by phone type
The code depends on what kind of line your business number rides on, not on the answering service. Here’s where to start.
Traditional business landline
In North America, star codes for forwarding are assigned by the numbering administrator. The North American Numbering Plan Administrator (NANPA) vertical service code list assigns these:
*72activates call forwarding;*73turns it off*68activates busy line/don’t answer forwarding;*88turns it off*90activates customer-programmable busy line forwarding;*91turns it off*92activates customer-programmable don’t answer forwarding;*93turns it off
An assigned code isn’t the same as a code your carrier has switched on. Plenty of business lines only have *72 provisioned, and some carriers charge for the conditional versions. If *92 gets you a fast busy or an error recording, call the carrier and ask for “call forward don’t answer” by name.
Cell phone on Verizon
According to Verizon’s call forwarding FAQ, you dial *72 plus the 10-digit number for immediate forwarding, *71 plus the 10-digit number to forward only calls you don’t answer or when you’re busy, and *73 to turn forwarding off. Verizon’s FAQ also notes that if you don’t have unlimited minutes, forwarded calls are billed as though you answered them on your phone.
That billing detail matters if the business number is an older plan with a minute cap. A busy storm week can burn through it.
Cell phones on GSM and LTE networks
Many other cell phones accept the network-level codes written into the ETSI and 3GPP TS 22.030 specification. The service codes are 21 for unconditional, 67 for busy, 61 for no reply, 62 for not reachable, 004 for all conditional forwarding and 002 for all forwarding. You register with two stars and erase with two pound signs:
**21*[number]#forwards everything**61*[number]**20#forwards unanswered calls after 20 seconds**67*[number]#forwards when you’re on another call**004*[number]#sets busy, no-reply and not-reachable forwarding in one go##002#erases every forward on the phone
Be careful with that last one. On a lot of cell plans, carrier voicemail is itself a no-answer forward, so wiping all forwarding can wipe the voicemail route too. Check with your carrier before you use it as your “undo” button.
VoIP and hosted phone systems
Cloud phone systems usually skip star codes. Log in to the admin portal and look for a section named something like “call handling,” “answering rules” or “call flow.” That’s where you set the ring timer, the overflow destination and the business-hours schedule in one screen. If your system also runs a phone menu, put the forward after the menu or instead of it. Our guide to what IVR is and why callers hate it covers why a four-option menu in front of the service costs you callers.
Set the timer so your own staff still get first shot
The no-reply timer is the setting almost nobody changes, and it decides how the whole arrangement feels to a caller. The ETSI and 3GPP TS 22.030 specification allows a No Reply Condition Timer between 5 and 30 seconds on phones that use the network codes.
Too short and the service answers calls your office manager was reaching for. Too long and the caller hangs up before the handoff happens. For a shop with a front desk, 15 to 20 seconds is a sensible starting point. For an owner who’s usually on a ladder, go shorter, because nobody’s going to get to that phone anyway.
Two more things to settle while you’re in there:
- Where calls go if the service can’t take them. Whatever the service’s own fallback is, make sure it doesn’t loop back to your line and bounce forever.
- Whether voicemail still exists. If your carrier voicemail picks up before the forward timer runs out, the caller hits your old greeting and the service never sees the call. Keep the voicemail pickup longer than the forward, or turn carrier voicemail off. If you do keep a greeting for nights, our after hours voicemail greeting scripts are built for that job.
Test the forward like a customer would
A forward that worked when you tested it from your own cell proves very little. Run these checks from a phone that isn’t on your business account:
- The no-answer test. Call the business number and let it ring. Time how long until the service picks up.
- The busy test. Have someone stay on the office line and call in from a second phone.
- The after-hours test. Call at 11 PM on a weeknight, not 11 AM on a Tuesday. Scheduled rules fail at night, and you won’t find out any other way.
- The caller ID check. Look at what number the service recorded. Some setups pass through the customer’s number; others show your own business number, which makes every callback go to yourself.
- The off switch. Turn forwarding off and call again. Make sure your line rings normally, so you know how to back out on a slow day.
Write down which code you used and where. Six months from now, when someone asks why the phone doesn’t ring, that note saves an hour on hold with the carrier.
Forward the number you already publish
Don’t change the number on your trucks, your Google Business Profile or your yard signs to get answering coverage. Forward the existing number and nothing customers see has to change. If the service doesn’t work out, you dial the off code and you’re back where you started.
Porting is a bigger commitment. The FCC guide to keeping your phone number when you change providers says you can keep your number when switching providers if you stay in the same geographic area, and warns not to cancel service with your current company before the new one starts the port. Run forwarding first. Port later, if ever, once you’re sure you’re staying.
If you’re still weighing what kind of service should sit at the end of the forward, compare the models in our AI receptionist vs answering service breakdown and what each one charges in the answering service cost guide.
FAQ
Q: Does call forwarding to an answering service cost extra? A: It depends on the carrier and plan. Some include forwarding at no charge, some charge for the conditional versions, and on capped plans the forwarded minutes can count against you. Ask your carrier whether “call forward busy” and “call forward don’t answer” are included on your line.
Q: Will callers know their call was forwarded? A: Usually not. They dial your number, hear a few rings, and someone answers. The only tell is the delay from the no-answer timer, which is why that setting deserves a minute of thought.
Q: Can I forward calls only after hours? A: Yes. On a VoIP system, set a business-hours schedule in the admin portal. On a landline or cell phone without scheduling, you’d dial the activation code at close and the deactivation code at open, which works until the first night somebody forgets.
Q: My carrier’s code didn’t work. What now? A: Codes vary by carrier and by what’s provisioned on your specific line. Call the carrier’s business support, ask for the feature by name (“call forward don’t answer”), and have them confirm the code and the ring timer on your account.
Q: Should I forward my main line or a separate number? A: Forward the main line you already publish. A separate number means updating every listing, and inconsistent phone numbers across your listings can confuse customers looking you up.
Point the forward at InstaNexus AI
Once the forward is set, the only question left is what answers at the other end. InstaNexus AI answers calls 24/7, captures the caller’s name, number and reason for calling, and asks your own intake questions on every call. When the call ends, you get an SMS and email summary with the caller’s details and a transcript.
Urgent calls get warm-transferred to a live person on your night and weekend on-call schedule. If nobody picks up, it falls back to voicemail and sends you an alert. For appointment-based work, it can book the job during the call into Google Calendar, inside your business hours. See how that plays out for your trade on the HVAC and plumbing pages.