Function and principle Analog user modules in the host (MPU) under the control of the MCU on the user board (ASL) to complete the detection and reporting on the status of the subscriber line. ASL is a terminal circuit portion of the user module. According to the number of connected analog line with the user board divided into 16 analog users plates and 32 analog user board CC0HASL veneer 32 analog user board, it can only be inserted in the user box 32. CC0HASL veneer implements the following functions: 32 analog user interface. Veneer with BORSCHT (fed, over voltage / current protection, ringing, monitoring, encoding and decoding, mixing, testing). Reverse polarity provides some special features (2, CID). The veneer provides software A / Mrate adjustable interface impedance is adjustable, adjustable gain feature. External wiring: user cable (32 of the subscriber line), and corresponding cable connected to the motherboard of user box interface. 32 user box 16 road users cable plug can be inserted, and both plugs were inserted in the uppermost and lowermost. CC0NASL (panel silkscreen A32) and offers 32 analog user port, complete analog subscriber circuit BORSCHT. Veneer by the subscriber line interface section and a control section. the veneer CC0HASL and CC0NASL difference is: The Road 16,17 port can provide CC0HASL reverse polarity function. the 32 Road CC0NASL port can provide reverse polarity.