Our return path optical transmitter modules for the MO and MDO node series were built with different parameters. The formerly popular types with 1 mW Fabry-Perot lasers should be upgraded by building in DFB lasers in order to fit the latest requirements generated by the new modulation technologies. The new laser can have an output power of 2 or 4 mW, and it is available with all the CWDM wavelengths beside the basic 1310 nm. The bandwidth limited versions can be rebuilt also with extended bandwidth of up to 200 MHz.. The upgrade task contains by default a fully comprehensive test procedure, which concerns not only the modified functions. After this a new label with modified type code and parameter list is sticked on the housing.