# BR-DE-6 Seller contact telephone must be provided

Under the German XRechnung profile for electronic invoicing in public procurement, the seller contact telephone number (BT-42) is a mandatory field within the seller contact group (BG-6). Public authorities require direct telephone reachability to clarify urgent billing inquiries, invoice discrepancies, or delivery receipt confirmations without causing formal rejection and re-submission delays.

## Problem Description

> **ERROR**: German XRechnung rule (KoSIT, BR-DE) · XRechnung 3.0

## Context and Significance

Missing telephone information in BG-6 causes immediate Schematron error BR-DE-6. German public sector verification gateways reject such invoices unconditionally.

## Solution

In your ERP or accounting master data, specify a valid business telephone number with area code or international country code (+49 ...). In UBL 2.1 syntax, populate <cbc:Telephone> inside <cac:AccountingSupplierParty><cac:Party><cac:Contact>. In UN/CEFACT CII syntax, populate <ram:TelephoneUniversalCommunication><ram:CompleteNumber> inside <ram:SellerTradeParty><ram:DefinedTradeContact>. Note that per rule BR-DE-27, the value should contain at least three digits and not consist of dummy placeholders.

- [Validate XML](/en/xrechnung-validator?source=resource&rule=BR-DE-6)
- [Convert invoice](/en/pdf-to-xrechnung?source=resource&rule=BR-DE-6)

## Valid Examples

- BT-42 = "+49 30 1234567"
- BT-42 = "089 987654321"

## Invalid Examples

- Seller contact group (cac:Contact / ram:DefinedTradeContact) includes name and email but omits cbc:Telephone / ram:CompleteNumber
- Telephone element populated with placeholder text such as "--" or "n/a"

## Code Examples

### Valid XML
```
<cac:Contact>
  <cbc:Name>Vertrieb / Kundenbetreuung</cbc:Name>
  <cbc:Telephone>+49 30 1234567</cbc:Telephone>
  <cbc:ElectronicMail>info@seller.de</cbc:ElectronicMail>
</cac:Contact>
```

### Invalid XML
```
<cac:Contact>
  <cbc:Name>Vertrieb / Kundenbetreuung</cbc:Name>
  <cbc:ElectronicMail>info@seller.de</cbc:ElectronicMail>
</cac:Contact>
```

## Affected Fields

- [BT-42 Seller contact telephone number](/resources/xrechnung/bt-42-seller-contact-telephone-number)
- [BG-6 Seller contact](/resources/xrechnung/bt-41-seller-contact-point)
- [BT-41 Seller contact point](/resources/xrechnung/bt-41-seller-contact-point)
- [BT-43 Seller contact email address](/resources/xrechnung/bt-43-seller-contact-email-address)

## Related Rules

- [BR-DE-2](/resources/kosit-validator-errors/br-de-2-seller-contact-required)
- [BR-DE-27](/resources/kosit-validator-errors/br-de-27-seller-contact-telephone-syntax)

## Validation Tools

- [Official KoSIT Validator](https://github.com/itplr-kosit/validator): Run the official KoSIT validator with the XRechnung configuration to check EN 16931 and XRechnung rules.
- [Convert PDF to XRechnung](/pdf-to-xrechnung): Find validation errors during conversion and review each correction.

## Related Resources

- [Official Specification](https://xeinkauf.de/xrechnung/)
- [Test Suite](https://github.com/itplr-kosit/xrechnung-testsuite)
- [All validation errors](/resources/kosit-validator-errors): Overview of the EN 16931, XRechnung and Peppol validation rules explained here.