Czech Republic voice guidelines
Voice calling guidelines for Czech Republic (CZ), covering reachability, caller ID formats, DTMF support, and emergency services.
Locale overview
| Field | Value |
|---|---|
| Country | Czech Republic |
| ISO code | CZ |
| Region | Europe |
| Dialing code | +420 |
Reachability
Czech Republic supports inbound and outbound calling for domestic, international, and toll-free number types.
| Call type | Inbound | Outbound |
|---|---|---|
| Domestic | Supported | Supported |
| International | Supported | Supported |
| Toll-free | Supported | Supported |
Domestic outbound requirement: For domestic outbound calls, use a Czech Republic phone number as the originating number.
Caller ID
Caller ID format varies by call type and direction.
| Call type | Direction | Format |
|---|---|---|
| Domestic | Inbound | E.164 |
| Domestic | Outbound | Local (non-guaranteed) |
| International | Inbound | E.164 (non-guaranteed) |
| International | Outbound | E.164 |
| Toll-free | Inbound | E.164 |
| Toll-free | Outbound | Local (non-guaranteed) |
DTMF support
DTMF signaling uses RFC 2833 format and is supported in both inbound and outbound directions.
Emergency services
Calls to emergency services numbers in Czech Republic are not supported. Do not attempt to route emergency calls through voice calling in this region.
Special requirements
For domestic outbound calls, the originating caller ID must be a Czech Republic phone number. Using a number from another country for domestic outbound calls is not supported.
Compliance note
These guidelines summarize carrier requirements at the time of publication and do not constitute legal counsel. Verify that your implementation complies with all applicable telecommunications regulations in Czech Republic.