Background work in various levels of speech coding is reviewed, including unconstrained coding and recognition-synthesis approaches that assume the signal is speech. A pilot project in HMM-TTS based speech coding is then described, in which a comparison with harmonic plus noise modelling is also done. Results of the demonstration project including samples of speech under various transmission situations are presented in an accompanying web page. The report concludes by describing and enumerating the shortcomings of the demonstration system that define directions for future work. This work is a deliverable for the armasuisse funded project “RECOD - Low bit-rate speech coding”