3.0FUNCTIONAL DESCRIPTION
3.1GENERAL
The EM405D provides a mechanical and electrical interface between an Ethernet bus and up to two M-modules. It utilizes an embedded microcontroller to provide buffering and command translation between the Ethernet interface and the M-modules. A simplified functional block diagram is shown in Figure 4.
+12VDC IN 
OR
HERE
TRG IN
TRG OUT
9-PIN DSUB
POSITION B POSITION A
Figure 4. Functional Block Diagram
3.1.1 Embedded Controller
The embedded controller is implemented using a high-performance microcontroller. The microcontroller executes system firmware that controls the translation between Ethernet and the M-module interface. The system firmware implements a simple command protocol that allows access to the M-modules I/O space, trigger mapping and carrier information and status. It also provides data buffering and fan control.
3.1.2 Ethernet Interface
The Ethernet interface provides the physical and logical connection to the EM405D allowing remote control of the M-modules. The EM405D is available with either wired 10/100 Base-T Ethernet or wireless Ethernet (Wi-Fi). The interface supports the TPC/IP protocol for control of the M-modules. It also supports DHCP, AutoIP, Telnet, HTTP and other standard protocols for device configuration and management.
