Voice double call, private dedicated line, voice interaction, total recall, direct charging of traffic, video call, multimedia video, SMS notification. What companies are there?

I only know most of the companies you mentioned. According to the keywords you provided, the functions of voice double call, private line, voice interaction and total recall can basically be realized on the automatic outgoing call system. The representative companies are Shangjing in Shanghai and Jin Lun in Shenzhen. With regard to the direct charging of traffic, Changhua Guoxin is engaged in mobile phone traffic. Video calls, multimedia videos, SMS notifications have face time, and QQ has improved services.