Where to apply for an airport transit visa?

My place of residence My visa application should be submitted to
Soudan Embassy of Switzerland in Khartoum 
Eritrea   Embassy of Switzerland in Khartoum  

Representation agreement

If a State does not have its proper visa section in a country or region, the delivery of a Schengen visa can be delegated to another Schengen State member with an agreement between both countries concerned.

The agreement allows the appointed representation to represent and handle Schengen visa applications within its own competence without consulting the other represented State.

Country / Region Schengen State represented by Switzerland
Soudan  Czech Republic 
Soudan Slovak Republic