GSM & USSD Codes Reference
A reference guide of useful GSM control codes for call management.
| Feature | Activation Code | Deactivation |
|---|---|---|
| Unconditional Forwarding | **21*Rufnummer# | ##21# |
| Forward when busy | **67*Rufnummer# | ##67# |
| Forward when no reply | **61*Rufnummer# | ##61# |
