When your business expands, more users and concurrent calls can be added easily to meet growing business needs through the telephony cards in the IP PBX.
U-4DTU, a T1 telephony card for North American Term, can be flexibly configured in PBX-U502/U503 by hot-plug mode to expand its functionality. It supports 4 T1 per board and any four boards of the same series and can be mixed according to your specific needs.