Yealink EXP38 expansion module is designed for improving the power and flexibility of Yealink IP phones. It features 38 fully programmable DSS keys each with a dual-color LED, connected to and controlled by the IP phone with an RJ-12 cable line. Yealink IP phones support the functions for IP-PBX such as speed dialing, BLF/BLA, intercom, call forward/transfer/hold/park/pickup/return on each of the programmable buttons on the EXP38. Yealink EXP38 is ideal for receptionists, administrative assistants, call center agents, power users, and executives who need to monitor and manage a large volume of calls on a regular basis.