Call Forwarding Codes: Busy, No Answer, *72 and **21*

The short answer

There are four kinds of call forwarding on a mobile line: forward everything (unconditional), forward when you are busy, forward when you do not answer, and forward when your phone is off or out of coverage. The last three are "conditional" because they only act when a condition is met.

The codes you dial depend on your carrier, as of October 2026:

• Rogers and T-Mobile use the international GSM-style codes: 21 for all calls, 67 for busy, 61 for no answer, 62 for unreachable, typed as *21*number# or **21*number# ^[1][2].
• Verizon uses its own short set: *72 plus the number for all calls, *71 plus the number for busy or no answer, and *73 to turn forwarding off ^[3].

For any other carrier, use its own support page; this article only gives codes those three publish.

Forwarding in one table

The mobile standard, 3GPP TS 22.082, defines four separate forwarding services, each a distinct setting with its own destination ^[4][5].

The service codes come from Annex B of 3GPP TS 22.030 ^[6][7]. They have been stable for a long time: a 3GPP change request approved in September 2000 shows the same table, with 21, 67, 61, 62, 002 and 004 ^[8].

Internet phone systems have the same three ideas: RFC 5359 shows SIP call flows for unconditional, busy and no-answer forwarding; in the no-answer flow the server cancels the ringing phone after a timeout and sends the call on ^[9].

Unconditional forwarding: when to use it, and the risk of forgetting it

The standard describes unconditional forwarding plainly: if it is active, "calls are forwarded no matter what the condition of the termination" ^[10]. Your phone does not ring at all. You can still make outgoing calls.

Use it when the phone should not ring at all: the owner is on a flight, the phone is being repaired, or a colleague covers for the day.

Sources: Rogers, T-Mobile, Verizon.

The risk is that it is invisible. Verizon's own page warns that "your phone won't ring again until you turn off call forwarding" ^[3]. T-Mobile describes the setting as one that "prevents calls to your number" ^[2].

Unconditional forwarding also silences your other settings. Under TS 22.082, if busy forwarding is set and you then turn on unconditional forwarding, busy forwarding goes "quiescent" (paused) until unconditional forwarding is turned off. The reverse order is rejected: if unconditional forwarding is already on, the network refuses a request to activate busy forwarding ^[11]. So a forgotten 21 can explain why your carefully set busy or no-answer rule "stopped working".

Habit: when you turn on all-calls forwarding, set a calendar reminder to turn it off.

Conditional forwarding: busy, no answer, unreachable

Conditional forwarding lets your phone ring first.

Sources: Rogers, T-Mobile, Verizon.

Three details matter in practice.

Verizon combines busy and no answer. Verizon calls *71 "No Answer/Busy Transfer" and says it sends calls on "when your phone is busy or when you don't answer after three or four rings" ^[3]. Its page lists no separate busy-only or unreachable code.

The no-answer timer can be set on GSM-style networks. TS 22.082 says the no-reply timer is between 5 and 30 seconds in steps of 5 seconds; if you never set it, a default chosen by the service provider applies ^[12]. T-Mobile exposes this: add ** and the number of seconds before the final #. Its own example is **61*18056377243**10# for a 10-second delay, and it offers "5, 10, 15, up to a 30-second delay" ^[2].

Carrier voicemail may get in the way. Rogers states that "conditional forwarding will not work when voicemail is activated" ^[1]. If unanswered calls should go somewhere other than your mailbox, ask your carrier how voicemail and forwarding interact on your plan.

The standard codes behind the carrier pages

The Rogers and T-Mobile codes look different (*21* versus **21*), but both follow one grammar from 3GPP TS 22.030, section 6.5.2 ^[13]:

SC is the service code from the table above; SI is the extra information, such as the destination number. The standard says the phone decides from context whether a single * means registration or activation: a forwarding request with a number in it is read as registration ^[13]. That is why Rogers's *21*number# and T-Mobile's **21*number# do the same job.

For no-answer forwarding, the standard allows a third field after the destination: SIB for the basic service group and SIC for the "No Reply Condition Timer", listed as 5 to 30 seconds ^[7]. Leaving SIB empty is what produces the double ** in T-Mobile's delay example.

Rogers's own table maps directly onto this grammar: "Temporarily Deactivate" is #21#, "Reactivate" is *21#, "Cancel" is ##21# and "Status" is *#21# ^[1]. Because the Rogers reactivate code carries no number, temporary deactivation keeps the stored destination; cancel ("erasure" in 3GPP terms) removes it.

Why *72 works on Verizon but *21 works on T-Mobile and Rogers

Rogers and T-Mobile publish codes that follow the 3GPP numbering (21, 61, 62, 67). Verizon publishes its own set, *72, *71 and *73, and does not list the 3GPP codes ^[3]. What this means:

• Use the codes on your current carrier's page. A code from another carrier may do nothing, or something else.
• After switching carriers, set forwarding again with the new carrier's codes and test; do not assume old settings carried over.
• Business calling products, landlines and internet phone services can use their own codes or a web portal. Check that product's guide.

Verizon also notes that you cannot forward to a number outside the U.S., and that if callers get a busy signal after you set forwarding, the first thing to check is that the destination number was typed correctly ^[3].

How to check and cancel forwarding

When calls go somewhere unexpected:

1. Check status. On Rogers, dial *#21#, *#67#, *#61# and *#62# one at a time; Rogers lists these as its status codes ^[1].
2. Clear everything conditional. T-Mobile lists ##004#, which "resets call forwarding to default" ^[2]. In the 3GPP table, 004 is "all conditional CF" ^[7]. Test afterwards to see where calls now go.
3. Clear all-calls forwarding. ##21# on Rogers and T-Mobile; *73 on Verizon.
4. On Verizon, *73 turns off both *72 and *71 forwarding, and My Verizon or customer service can also change it ^[3].
5. To change the destination on Rogers, cancel the existing forwarding first, then set it again with the new number ^[1].
6. Test from another phone, once per condition: let it ring out, call while you are on a call, call with the phone off.
7. Write down the destination set for each condition.

Forwarding to an auto attendant vs. letting the business number ring you

Option A: the business number rings your mobile. Callers dial the business number. The auto attendant greets them, they choose an option, and the system calls your mobile. Your mobile needs no forwarding codes. The ring time and what happens when nobody answers are set in the menu, not on the phone.

Option B: your mobile forwards to the business number. Callers dial your mobile; unanswered or busy calls go to the business number and hear its menu. This uses the codes above.

Points to check with either option:

• Carrier voicemail can answer first. In option A, if your mobile has its own no-answer forwarding to carrier voicemail, that mailbox may pick up before the menu's ring time ends, so the call never reaches the next person or the business voicemail. Our article on forwarded calls, caller ID and voicemail tests covers how to test for this.
• Avoid loops. If your mobile forwards to the business number, and a menu option rings that same mobile, a call can bounce between them. Do not combine option B with a menu option that rings the forwarding phone.
• Match the timers. If your mobile's no-answer timer is shorter than the menu's ring time, the phone's own forwarding can take the call before the menu moves on. On T-Mobile you can lengthen it to 30 seconds with the delay code above.
• Plan the "nobody answered" path in the menu. An overflow template for when nobody answers is a better place to decide this than a phone setting.

FAQ

Why does my forwarded call go to voicemail first? Often because carrier voicemail is set as the no-answer or unreachable destination on the phone being called, and its timer runs out first. Rogers notes that conditional forwarding does not work while voicemail is active ^[1]. Check status codes, then test.

Does forwarding cost minutes? It can. Verizon says there is no monthly fee on current plans, but "airtime charges still apply to all forwarded calls", and additional per-minute charges may apply ^[3]. Other carriers set their own terms; check your plan.

How do I forward a landline? Landline codes are set by each phone company and are not covered here. Check your provider's support page.

Is "unreachable" the same as "no answer"? No. Unreachable applies when the phone is off, out of coverage or not registered on the network ^[14]. No answer applies when the phone rings but nobody picks up.

Educational information, not legal or contractual advice; codes and plan terms change, so confirm with your carrier.

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