Commercial Fixed Wing
Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Communication Breakdown; Distraction; Situational Awareness
ATC Issue All Types
Flight Crew Requested ATC Assistance / Clarification
Airspace Structure; Human Factors; Staffing
Climbing to 160 on the ZZZZZ departure we were given a radio handoff to ZZZ TRACON and either we had put the wrong frequency in; or were given the incorrect one; but we tried to establish communication with the Controller who we could clearly hear speaking.  The Controller came back to our check in with; 'Everybody listen up...I'm working a bunch of frequencies; and have like 20 aircraft all trying to reach me. Just ident and I'll get back to all of you shortly.'  So we sent an ident; and waited. After a few minutes; we queried again. The calls went unanswered. We waited a few more minutes; still at 160 on the departure;  and tried again. This time we received the response; 'Aircraft at 160; ident and I'll call you in a few minutes.'  So we did.  After an eternity; we finally demanded a specific call sign response; to which the Controller told us we were on the wrong frequency and go back to previous one.  So we did; to which the Controller then gave us the correct one. The new Controller was advised by us of the frequency error.   Cause - Over worked Controller; lack of CPDLC to guarantee correct frequency; and Controller using non-standard phraseology when answering radio calls. Suggestion - Widespread use of CPDLC for handoffs; and controllers adhering to correct phraseology when addressing check-ins to a frequency.
Air carrier Captain reported checking in and hearing the Controller tell everybody to stand by.  They continued on assigned heading and altitude; finally being told they were on the wrong frequency. Controller reportedly was working multiple frequencies.