Roaming on ATT in USA with Telcel cellular phone

Heading NOB for a few days and will use my Telcel celular instead of ATT go-phone as I have in the past.  Just want to confirm that when I'm roaming on ATT I'd use the same dialing protocal for calling USA phones, land line or cell, and sending SMS text message to cells, as if I were using an ATT USA based cell phone.  

Can someone confirm the above or tell when where I'm off base if I'm wrong.

hueco_negro wrote:Heading NOB for a few days and will use my Telcel celular instead of ATT go-phone as I have in the past.  Just want to confirm that when I'm roaming on ATT I'd use the same dialing protocal for calling USA phones, land line or cell, and sending SMS text message to cells, as if I were using an ATT USA based cell phone.  

Can someone confirm the above or tell when where I'm off base if I'm wrong.

Works for us the same as if we were using a US or Canada cellphone.
Just dial the 10 digit number, and pay the roaming charge.

OK thanks, that's kind of what I thought but just wanted to be sure.