Update (October 11, 2012): Well, it looks like Google has now extended the service to all mobile operators, after 8 months of the service going live in India. While there is still no official announcement from the company yet, the Google Chat support page has been updated to reflect this change.
When we checked the service, we were able to send a text message to Airtel number, however we weren’t able to send messages to a Vodafone number which is currently under DND (Do Not Disturb registry), and received an error message stating that the person did not receive the SMS. We feel Google should’ve devised a way to allow users to check whether a specific number is on DND or not, before sending the SMS. Also, it could have registered with the TRAI under the non-commercial communications services category for an exemption, similar to Jaxtr, Hike and others.
Previously (March 9, 2012): Google seems to have silently expanded its Gmail SMS chat service to India, although we are not quite sure when it went live since there was no official announcement from the company. Not to be confused with Google’s Push SMS service, which allows users to broadcast messages through channels, this service seems to be more focussed on one-to-one communication and allows Gmail and Google Apps users to send text messages through the Google Talk widget present in dashboard.
How it works? One can enter the phone number they wish to send a message or select one of the existing contacts through the chat widget, following which a popup window opens up through which they can send an SMS. If the contact replies, this message will appear as a reply in the same chat thread. If you are familiar to how Google Chat/Gtalk works, it works in a similar fashion, except for the fact that you are sending an SMS instead of an IM (Instant Message).
Sadly, this service is not operator-agnostic and seems to work only on Aircel, Loop Mobile, Reliance, and Tata DoCoMo phone numbers at the time of writing this article. Update: The service has now been rolled out to all mobile operators in India.
SMS credits: Google’s SMS service works on a credit system: Each Gmail user is initially allotted 50 SMS credits which can be used to send text messages through their Gmail/Google Apps Dashboard. Each time the user gets a reply to his message through SMS, his credits will increase by five until it reaches the maximum of 50. Google will also increase the SMS credit back to one after 24hrs in case the user runs out of SMS credits.
No Option To Buy Credits? There currently seems to be no option to buy higher SMS credits. Instead, Google states in their own SMS support page that one can send an SMS from a phone and reply to the message multiple times through their phone to increase their SMS credits. Since the conversation happens over a premium number on the phone, Google said that users will be effectively buying credits by paying the telecom operator for these messages.
Other Services: Yahoo has been offering a similar SMS service for quite some time, wherein users of Yahoo Messenger can send text messages to any mobile phone. Way2online, which recently acquired the Hyderabad SMS portal 160by2, operates a person-to-person (P2P) messaging portal called Way2SMS.com. In Novermber 2011, Sabeer Bhatia had relaunched Jaxtr as JaxtrSMS, a mobile app which allows users to send national and international text messages for free.