Working mother Kumari Ranasinghe looks forward every day to a telephone call from someone who hangs up on her immediately -- her 12-year-old son who is making the call to let her know he has left school. It's a supremely cost-effective method of keeping in touch that has swept Sri Lanka where daily bloodshed, despite a truce in the civil war, has many people living in fear for their lives and those of loved ones.
"Two beeps (rings) on my mobile after an hour, I know he has got home safely," says 37-year-old Ranasinghe who works as a secretary in the jittery capital where security is tight amid fears of Tamil rebel bomb attacks. Mother and son are part of the new "ring cut" generation that has spread across Sri Lanka and other Asian countries.
A growing number of mobile phone owners use "missed calls" to communicate without answering incoming calls, according to telecom researchers here.
The island nation of 19 million has more than five million mobile phone subscribers with the majority using pre-paid subscriptions.
Call rates of 5.00 rupees (0.05 U.S. cents) per minute are too expensive for the many people in this country who earn less than 100 dollars a month, so they pre-pay as little as 20 rupees (0.19 U.S. cents) for a SIM card that will then last months as they mostly use their phones to "ring cut" on the missed calls function.
The system has already found favour with about 15 percent of the mobile phone users in Sri Lanka who buy phones for around 30 dollars, according to cellular operators.
"It's a secret language of saying 'I'm thinking about you' or 'Call me back'," says Ayesha Zainudeen, researcher at LIRNEasia, a regional telecoms think-tank that studied mobile phone usage patterns in Sri Lanka, India, Pakistan, the Philippines and Thailand.
"It's a segment that is fast catching on among young and rural people who see it as a form of affordable communication," Zainudeen told AFP in a recent interview.
Use of the missed calls function, or beeping as it is also known, involves dialling a number and hanging up before the call is answered; the phone's internal log records the number the call came from and at what time.
Most beeps are requests to the mobile owner to call back immediately, but beeps can also send a pre-set messages such as "answer now" or "I miss you". "I would often hear someone say, 'I'll give you a ring cut when I get there'," says undergraduate Roshan de Silva, who uses missed calls for pre-arranged messages among his friends.
Mobile phone companies offer incoming calls for free and make money when a connection is completed. The companies declined to comment on the practice, but another analyst says it impacts the bottom line and network quality.
LIRNEasia's lead economist Harsha de Silva told AFP: "Missed calls are not good for the networks -- less revenue; not good for the state --less taxes; and not necessarily good for the user -- networks get blocked and we can't talk."
Of the five nations, only the Philippines beat Sri Lanka in the "ring cut" race, according to the LIRNEasia study that surveyed around 9,000 low income earners aged between 18 and 80 years old.
In the Philippines, 65 percent of mobile phone owners use missed calls, compared with Thailand's 40 percent, India's 36 percent and Pakistan's 39 percent, said Zainudeen. In addition, many people used telephones at their workplace, or landlines to return a "ring cut," further avoiding payment on mobile networks.
Rohith Perera, 28, who on average receives 10 to 15 missed calls during office hours daily, notes that some of his colleagues also used it as a ruse to skip long meetings, as executives will excuse themselves to answer calls outside the meeting room.
"Sometimes outsiders want you to call back from workplaces, because it's the office that picks up the cost of the call," Perera said.
But "ring cut" signals can also backfire. Roshan de Silva says he has "missed" meeting his girlfriend when his phone was on silent mode. "It's also a disaster when the networks are busy and you can't get through to leave a missed call."