The Tandy SL and TL series of computers were updates of the SX and TX, respectively. In addition to offering redesigned cases, the machines offered a more integrated motherboard with improved graphics and sound capabilities while dropping composite video output. The graphics controller now supported resolution as well as a Hercules Graphics Card-compatible, mode for monochrome monitors. Sound capabilities now included an 8-bit monaural DAC/ADC, which was similar in function to parallel port sound devices (such as the Covox Speech Thing and Disney Sound Source) but was extended to support DMA transfers, microphone input capability, and sampling rates up to 48 kHz. The SL/TL lines allowed the on-board floppy controller, parallel port and serial ports to be disabled, which the earlier models did not.