Alarm.com specifically designed their two way voice to make it impossible for the central station to initiate the connection to the panel. The connection has to be initiated by the panel. Regarding the 2GIG panel, the manual says:
"When the Control Panel connects with the operator, it will beep once per second (every 6 seconds with a cell radio connection). The beep alternates between two tones and indicates the Control Panel is waiting for a session command. If the operator fails to issue a command within one minute (three minutes with a cell radio connection), the call is terminated. Once the operator presses a command option, the beeps will stop and a 5 ‐ minute audio session will start (3 ‐ minute audio session with a cell radio connection).
When 2‐way voice communications have been established, the Central Station operator can use … telephone keys to control the communications. Each time the operator uses a command key, the session is extended for five additional minutes (three minutes with a cell radio connection). During the last minute of communications, the system beeps twice every 15 seconds to indicate that time is running out."