Where is the area code of 1203?

Answer 1

North American telephone area code +1 203 is for the southwestern part of the US state of Connecticut, including New Haven, Stamford, and Greenwich.

UK telephone area code +44 1203 (or 01203 within the UK) was previously used for Coventry, which is now in area code +44 24 (or 024).

(The plus sign means "insert your international access prefix here." From a GSM mobile phone, you can enter the number in full international format, starting with the plus sign. The most common prefix is 00, but North America (USA, Canada, etc.) uses 011, Japan uses 010, Australia uses 0011, and many other countries use different prefixes.)