# TELCAL library interfaces

The user may interact with the TELCAL library at different levels:

- Direct call of very general fitting routines (e.g. see fit_1d).
- Direct call of high level functionalites (e.g. solve of a cross pointing scan).
- Use of the TELCAL language to access the same high level functionalities (as the GILDAS GTVL library is mainly accessed through the GTVL language).

Subsections

- Interfaces
- Derived types