Inmates in US county jails (most county jails) have a Chirp phones / devices (also known as Churp phones) which they can use to send and receive texts / SMSs. Unfortunately it is quite expensive, $0.10 per incoming text / SMS and $0.10 per outgoing text / SMS. There is http://tysongovek.blogripley.com/2885193/how-to-text-inmate-in-county-jail