Yealink EXP50. Brand New Includes One Year Warranty.. Item # EXP50.. The Yealink EXP50is an expansion module which features a 272x480 Graphic LCD and 20 physical, dual-color LED programmable keys. By programming the keys, you can set the keys for speed dial, BLF or BLA functionality. In addition, three accessible pages allows you to change screens and simplifies navigability for the end user and also have 20 additio