---
type: concept
title: Private Telephony Usage
tags: [policy, billing, authentication]
related: [tk-system, zentraler-nutzeraccount]
created: 2026-06-30
updated: 2026-06-30
sources: ["output/rz_uni_greifswald_de_dienste_technische_infrastruktur_telefonie_private_telefong.md"]
---

# Private Telephony Usage

**Private Telephony Usage** refers to the policy and technical workflow allowing university staff to use the [[tk-system]] for non-business calls.

## Technical Workflow
To signal a private call and trigger the authentication process, users must use a specific prefix:
- **Private Call Prefix**: `850`
- **Authentication**: After dialing the prefix and the destination number, the user must enter their personal phone number PIN.

## Billing Process
Private calls are not free and are subject to the following billing rules:
- **Frequency**: Quarterly billing.
- **Minimum Amount**: If the total cost for a quarter is less than **5.00 EUR**, the amount is waived.
- **Notification**: Invoices are delivered via the user's university email.
- **Dispute Window**: Users have 8 weeks to lodge objections with the [[universitatsrechenzentrum-urz]].

## Requirements
- An active [[zentraler-nutzeraccount]] is mandatory.
- Use of the official university email account for billing notifications.
- Strict confidentiality of the phone PIN.