... -in over 16 types of I/O Modular Supported service: FXS, FXO, Ethernet, V.35, X.21, V.24, G703 (64K), RS ... technical & quality parameter than ITU-T standard, support FXS-FXO-FXS analogue multi link relay. FXS/FXO/lease line/E&M voice detail parameter support ... : E1 uplink , 4 line FXS/FXO PCM4F: Fiber optical uplink , 4 line FXS/FXO PCM4-2E4RS: E1 uplink, 4 line FXS/O + 4Ports Rs232/485 ...