At the beginning of Borderlands 3, Claptrap says that the original ECHO-2 communicators were recalled and rebranded as grenades due to spontaneously exploding. Sure enough, the ECHO-2 can be found and equipped
Borderlands 3 ECHO Device Messenger Bag - Numskull
Borderlands Phone Cases - iPhone and Android | TeePublic
Use a Raspberry Pi to Build a Functional Borderlands Echo Device - Hackster.io