Continuous wavelength tuning of 3-section DBR lasers by current injection has been previously demonstrated over 4.4 nm, and over 10 nm in quasi-continuous manner1. The fast wavelength-switching properties of these devices, however, are not well known. Interest in fast wavelength-tunable lasers is enhanced by their potential applications in a variety of multiwavelength network architectures2. In this paper, we present the first use of a 3- section DBR laser to switch wavelengths and modulate (either intensity or FSK) the data simultaneously on the same device, so as to simulate the operation of a tunable transmitter in a multiwavelength packet switch. The advantages of using a single device for both fast wavelength-switching and direct data modulation are significant: the elimination of external modulators improves both the simplicity of the implementation and the available power budget.