B737 Undifferentiated or Other Model
Air Traffic Control Fully Certified
Air Traffic Control Time Certified In Pos 1 (yrs) 17.4
Distraction; Situational Awareness
ATC Issue All Types; Conflict Airborne Conflict
ATC Equipment / Nav Facility / Buildings
I was working and sector above me asked me to key their frequency because they believed that they lost frequency. I couldn't change their frequency. The CIC then asked if I had my frequency. I had tried to ship an aircraft prior but then tried another and no response. [Operations Manager] then came down the aisle and said switch to VTABS [Voice Switching and Control System Training and Backup Switch]. I proceeded to plug into D-side position PRE-jack. My frequency still wasn't working. I called ZME Calico sector to try they to give my Aircraft X. No luck reaching Aircraft X. I then plugged into D-side headset jack and broadcast for Aircraft X. I had never gotten a response but Aircraft X started descending at 3 mins till loss of separation and 4 mins till impact. We were CPDLC testing at the time of the event. I needed a D-side but was unable to get help because I needed to communicate with aircraft and there was no position available to help me.
Kansas City Controller reported radio problems in the area and then a loss of separation due to the radio failure.