What does the two letters (RM,BX,AD) etc in the name of SMS sender denote in India?

The two characters in the name of the bulk SMS sender denote the provider (1st character) and the region (2nd character) through which the SMS was sent. Below is the table to look up the provider and region. 

Provider List			Region List
A	Airtel		A	Andhra Pradesh
B	BSNL		B	Bihar
C	Datacom Solutions		D	Delhi
D	Aircel		E	UP-East
E	Reliance Telecom		G	Gujarat
H	HFCL Infotel		H	Haryana
I	Idea		I	Himachal Pradesh
L	Loop Telecom		J	Jammu & Kashmir
M	MTNL		K	Kolkata
P	Spice Telecom		L	Kerala
R	Reliance Communications		M	Mumbai
S	S Tel		N	North East
T	Tata Teleservices		O	Orissa
U	Uninor		P	Punjab
V	Vodafone		R	Rajasthan
W	Swan Telecom		S	Assam
Y	Shyam Telecom		T	Tamilnadu
			V	West Bengal
			W	UP-West
			X	Karnataka
			Y	Madhya Pradesh
			Z	Maharashtra

Reference: NDNC India