...
A tandem call is a connecting call in a telephone network, coming into a switch through one trunk and transferred out again through another.
Call types
| Call ID | Call type |
|---|---|
| 1 | Outgoing call |
| 2 | Outgoing failed to connect call |
| 50 | Outgoing operator-assisted call |
| 100 | Answered direct dial call |
| 101 | Answered transferred call |
| 150 | Abandoned direct dial call |
| 151 | Abandoned transferred call |
| 200 | Internal call |
| 250 | Internal failed to connect call |
| 300 | Feature call |
| 400 | Tandem call |