Isert Other Carrer Sim self-help card card card and if phone sows any message like below list so your Attt self Blackberry Q10 phonoe is lock with other Carier Sim Card so your phono is Unlocked.
Insert Other Carrier Sim card. if phone shows any message like below list so your At&t Blackberry Q10 phone is locked. if it accepts other Carrier Sim Card so your phone is Unlocked.