We are programming company. One guy is seeking jobs and talking to clients. Then when the job terms are negotiated, a project gets its own project manager and programmers. 

Once a project is started, who should talk to the client about project-specific things? If there is a coding problem, then it's obviously a developer that will have such conversations. 

However, should the PM take on all further conversations with the client, or should it be left to person who negotiated the job terms? It seems to me that the PM would be a better choice than the negotiator once the project has started.