We report on a fully functional 2.5-Gb/s electroabsorption (EA)-modulated wavelength-selectable laser module meeting all long-haul transmission requirements for stability, chirp, power and linewidth over 20 channels on a 50-GHz grid. Based on a highly integrated InP chip comprising a distributed Bragg reflector (DBR) laser, semiconductor optical amplifier, power monitor, and EA-modulator, the compact transmitter module also contains optics and control circuits necessary to ensure simultaneous long-term wavelength and mode stability. We have achieved 2.5-Gb/s transmission on all 20 channels over 680 km of standard fiber.