PSTN Access

Outgoing calls (to PSTN):
- ANI transformation
  - Called number
  - If no DID range, transform all directory numbers to (single) PSTN number.
  - If DID range, add prefix
- DNIS transformation
  - Calling number
  - Strip access code

Incoming calls (from PSTN)
- ANI transformation
  - Called number
  - Transformed to full PSTN number and add access code
  - Consider TON
- DNIS transformation
  - Calling Number
  - If DID range, strip PSTN prefix to directory number
  - If no DID, route call to attendant or IVR application