India's largest bank is turning to one of the country's smallest technology companies for a new minimalist cash machine it hopes will solve the subcontinent's chronic financial services shortage.

State Bank of India (SBI) has 10,000 branches, the second largest network in the world, but struggles to reach the farming communities that make up 70 per cent of India's population.

About 85 per cent of India's workers are employed in the "unorganised sector" – where wages are paid in cash – and at least half do not have a bank account. Hoping to reach the underbanked masses, SBI is trialling a new automatic teller machine (ATM) that costs a tenth of the price of conventional models and is cheap enough to deploy in areas where the average transaction is 100 rupees (£1.25).

Built around a pared-down software platform and connected to a bank via the web, the Gramateller ATM makes do without the frills found on its Indian city cousins, such as the ability to make payments to the local temple.

Instead it includes features useful for country living. A fingerprint scanner provides an identification system suitable for a country where 70 per cent of the population is illiterate. It runs on just 60 watts of electricity – a fraction of the 3,000 watts required by a conventional ATM – to cut the cost of supplying backup power in areas where blackouts are common. The new generation ATM also emits far less heat, which means unlike a traditional cash machine, it does not need to be housed in an air-conditioned closet.

Moreover, though it will only handle a single denomination of currency, the Gramateller can take deposits and deal with dirty and crumpled notes – helpful, since rural users are often suspicious that crisp new cash is forged.

The machine has been developed by Vortex, a Madras-based technology start-up funded by a 2 million rupee (£60,000) investment from Aavishkar, a specialist "micro venture capital" firm that is backed by groups including Deutsche Bank. ICICI, India's largest private bank, is also piloting the technology while one of Indonesia's largest retail banks has told Vortex it will "buy as many ATMs as the company can build" – provided the Gramateller passes its current field tests.

"Manned branches are too expensive; conventional ATMs cost too much and are not equal to the challenges of rural environments," Lakshmimarayan Kannan, of Vortex, said. "We built the Gramateller to bring banking in reach of those not covered today."

Comparisons with developed economies suggest the market for the minimalist ATM is potentially massive. In the US, where credit cards are common, there is a cash machine for every 1,000 people. In India, where cash is still king, there are only about 30,000 machines in the entire county – one for every 43,000 people – and most are densely packed into big cities.

However, the Gramateller is only one of several "branchless banking" models being tested around the world. In the Philippines, for instance, Globe Telecom customers can operate electronic accounts through mobile phones and similar systems are being used across Africa. In India ICICI already uses microfinance institutions, which specialise in granting tiny amounts of credit, as retail agents.

Against mobile-phone based systems, the Gramateller may be relatively vulnerable to thieves. However, Mr Kannan points out that it will carry only about a fifth of the amount of money found in a city ATM. "There won't be a need to have very much cash in our cash machine," he said. "Actually, there are likely to be plenty of assets around it worth more."

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