ATT: [ten-digit number]@txt.att.net. Example: 2065551212@txt.att.net
Verizon: [ten-digit number]@vtext.com. Example: 2065551212@vtext.com
T-Mobile: [ten-digit number]@tmomail.net. Example: 2065551212@tmomail.net
Sprint: [ten-digit number]@messaging.sprintpcs.com. Example: 2065551212@messaging.sprintpcs.com