The 'ABT8996 10-bit addressable scan ports (ASP) are members of the Texas Instruments (TITM) SCOPETM testability integrated-circuit family. This family of devices supports IEEE Standard 1149.1-1990 boundary scan to facilitate testing of complex circuit assemblies. Unlike most SCOPETM devices, the ASP is not a boundary-scannable device, rather, it applies TI's addressable-shadow-port technology to the IEEE Standard 1149.1-1990 (JTAG) test access port (TAP) to extend scan access beyond the board level. Conceptually, the ASP is a simple switch that can be used to directly connect a set of multidrop primary TAP signals to a set of secondary TAP signals for example, to interface backplane TAP signals to a board-level TAP. The ASP provides all signal buffering that might be required at these two interfaces. When primary and secondary TAPs are connected, only a moderate propagation delay is introduced no storage/retiming elements are inserted. This minimizes the need for reformatting board-level test vectors for in-system use.