These sms's sent by Banks, Service Providers, Social Networking sites, Companies and many other recognized organizations, institutes that have started prefixing something like LM, MM, BT, TA, AD, ID, AT, VK…etc. These SMSs originates from a Bulk SMS provider.the new TRAI regulation insisted bulk SMS providers to restrict the “Sender ID” to minimum 6 characters.
Three characters should be used to specify who is the bulk SMS service provider & where it’s originated from. Say for example: WAY2SMS sends an SMS to you using bulk SMS provider located at MUMBAI which uses Loop Mobile.You will receive it as LM-WAYSMS. First character specifies which service provider the message is being originated & the second character specifies from which location it’s originated. Here is the table which has details of these SMS codes: