The TP3406 is a complete monolithic transceiver for data transmission on twisted pair subscriber loops It is built on National's double poly microCMOS process and requires only a single a 5 Volt supply Alternate Mark Inversion (AMI) line coding in which binary `1's are alternately transmitted as a positive pulse then a negative pulse is used to ensure low error rates in the presence of noise with lower emi radiation than other codes such as Bi-phase (Manchester) Full-duplex transmission at 144 kb s is achieved on a single twisted wire pair using a burst-mode technique (Time Compression Multiplexed) Thus the device operates as an ISDN `U' Interface for short loop applications typically in a PBX environment providing transmission for 2 B channels and 1 D channel On 24 cable the range is up to 800 meters System timing is based on a Master Slave configuration with the line card end being the Master which controls loop timing and synchronisation All timing sequences necessary for loop activation and de-activation are generated on-chip Selection of Master and Slave mode operation is programmed via the Microwire Control Interface A 2 048 MHz clock which may be synchronized to the system clock controls all transmission-related timing functions