EMB ERJ 145 ER/LR
Flight Crew Air Transport Pilot (ATP)
Communication Breakdown
ATC Issue All Types; Conflict Airborne Conflict
Air Traffic Control Issued Advisory / Alert; Air Traffic Control Issued New Clearance; Flight Crew Became Reoriented; Flight Crew Took Evasive Action
Human Factors
We were given a descent to FL200. After the clearance was given; I commented about there must be traffic because they didn't give us HAYED at 19;000 which is what we had just briefed; planned; and built into the FMS.Passing FL230 ATC called traffic off to our right at FL220 (they did not state it was converging). We responded that we were looking I zoomed the TCAS scale to 12. Passing approximately 22;700 ATC ask us to verify descent clearance; but was stepped on. I was unable to respond due to radio congestion; but seeing traffic off of our right on TCAS that was now -600 and seemed to be closing; but passing off our right I took the controls and used Touch Control Steering (TCS) [to set] the vertical speed to zero (Leveled at 22;400) and answered the controllers second call telling him we were given FL200. The controller issued us a climb to FL230 and before we got there he issued a descent to cross HAYED at FL190. No RAs were issued.The threats were traffic in our vicinity; the heavy radio congestion; and possibly either a misunderstood clearance or a misgiven clearance. In the future I will be more proactive when it comes to ATC clearances that seem to be different than the normal flow or different to what we are expecting.
EMB145 Captain reported being cleared to descend to FL200; but a conflict developed with traffic at FL220 and the reporter took evasive action.