Nokia DX200

The DX200 telephone switching exchange by Nokia was created around 1978 upon Intel's brand new 16-bit 8086 processor. The software architecture was based on easy implementation of specifications written in SDL and the implementation language was PLM. During 1980s the code generation was somewhat automatized with TNCODE macro processor. More detailed variant of SDL (SDL-88) was utilized in a new in-house specification and implementation language TNSDL, which allowed more advanced programming and testing tools and fully automated code generation.