Keep your Airtel number active while abroad

Keep an Airtel number active abroad by leaving 20 rupees or more in the main account. After 90 days without a call, an outgoing SMS, data, or a value-added service, Airtel may deactivate the line if that balance is under 20 rupees. At 20 rupees or more, 20 rupees comes off every 30 days and extends the non-usage period by 30 days. A year of those deductions is about 240 rupees, arithmetic from that 20, if the balance still covers each one. Plan benefits are a separate clock: after a grace of up to 15 days they will be suspended without a recharge of at least 128 rupees.

The voucher clock, which runs first

The plan benefits stop long before the number does. Airtel's prepaid plan voucher terms state that "in case of non-recharge with a voucher of Minimum Rs. 128 or above post the grace period, all the services will be suspended", and that during a grace period "of up to 15 days" after the validity period ends, Airtel "reserves the right to provide the plan benefits in a curtailed manner at its own discretion".

Suspended services are not a lost number. It is an uncomfortable state to be in from another country, though, because the things you might use to reset the second clock are the things that have been switched off.

The number clock, and what keeps it from running

The condition for losing the number has two halves, and both have to be true. The same terms say the connection "will be deactivated if there is no voice/ video call (outgoing or incoming) or an outgoing SMS or a data session (upload or download) or usage of Value Added Services, for a continuous period of 90 days and in case the main account balance is less than Rs. 20/-, at the discretion of Airtel".

Note the parenthesis: "(outgoing or incoming)". On Airtel's wording, a call that comes in and is answered counts as usage, the same as one you place. That is written down here and it is not written down everywhere, which is why the comparison sits on all carriers.

The second half is the balance. Keep more than twenty rupees on the account and the rule above cannot fire, because the deactivation condition requires the balance to be under twenty.

What twenty rupees buys, and what it costs

Airtel spells out the mechanism. Per the terms, "if the subscriber main account balance is Rs. 20/- or more, a number retention charge of Rs. 20/- for every 30 days will be automatically deducted and the non-usage period will be extended by 30 days".

Thirty days at a time, twenty rupees a time. Over a year of silence that is roughly 240 rupees in retention charges, which is arithmetic from Airtel's own figure rather than a price on a shelf. Keeping plan benefits alive as well is a separate and larger cost, governed by the 128 rupee voucher rule above.

The fifteen days after

If the line does get deactivated, the terms give a window: "upon deactivation, all account balances will be forfeited and a grace period of 15 days will be provided within which the subscriber can retain the deactivated number by paying a fee of Rs. 20/-", according to the same page. Two things in that sentence matter beyond the fifteen days. The balance is forfeited, so whatever you left on the account to protect the number is gone. And the twenty rupee fee is the regulator's ceiling, described on the India page.

Before you fly

• Work out which clock you care about. Keeping the number costs twenty rupees a month; keeping the plan costs the voucher price.
• Put enough balance on the account to survive the trip's worth of thirty-day deductions.
• On Airtel's wording, answering a call from home counts as usage.
• If the point of the number is verification codes, bank OTP abroad is the other half of the problem.