Yes, many different providers depending on the area and manufacturer.
I was thinking that the poster was wondering if CPDLC uses the ACARS 'system' on the aircraft for communication.
There are SITA and ARINC networks.
ACARS systems are designed for the transmission of character-based messages to and from the aircraft, whereas the CPDLC and ADS applications intended for the ATN were defined using a binary bit-coded message set.
Last edited by underfire; 13th November 2016 at 00:51.