Following the break-up of Czechoslovakia in 1993, the successor states, the Czech Republic and Slovakia, continued to share the 42 country code until 28 February 1997, with the Czech Republic then adopting 420 and Slovakia adopting 421.[1]
On September 22, 2002, the Czech Republic adopted a closed numbering plan, with nine-digit numbers used for local and national calls, and the dropping of the trunk code 0.
Before the change, the following arrangements would have been made for calls to Brno:
Local call: xx xx xx xx
National call: 05/xx xx xx xx
International call: +420 5 xx xx xx xx
After the change, the dialing arrangements for calls to Brno were as follows:
O2 offers several over-the-phone information services for a fee. Note that many of the services are offered only in Czech:
Info Line (Czech Number Directory): 1180
Info Line (Foreign Number Directory): 1181
Operator for changed numbers (re-numbering): 141 11
Information on air quality: 141 10
Exact time: 141 12
Weather: 141 16
Medical Information: 141 20
Operator for international phone calls: 133 003
Prefixes
The first 1–3 digits (after +420) of the telephone number indicates location or network. For mobile phones, since there is number portability, the mobile phone code only indicates the original operator. For example, when a person calls a number starting with 73 (T-Mobile) but had been ported to another operator, a short voice message in Czech and English is played stating "you are calling out of a T-Mobile network" before the ringing tone. It is possible to disable this voice message.
601 – O2 Czech Republic (formerly NMT, numbers were ported to GSM in 2006; also used as part of the PPP log-in when dialling in the CDMA network) (formerly named EuroTel)