When you buy an I-7188E2 -MTCP controller, it already has the default Modbus firmware installed in Flash memory. The default firmware has the follows features:

• Supports VxComm technique for every COM port of controllers 
  If serial devices don't support Modbus/RTU, you can still access these devices. But need to install VxComm driver on host PCs and assign a COM port number to link to the remote COM port (of I-7188E2 -MTCP). After that, serial clients can access these remote serial devices via standard RS-232 functions.
• Allowed multi-client (or master) access simultaneously 
  Different I-7188E2 -MTCP controller supports different client numbers connect to. Please refer to our FAQ on web for more detail. 
  http://www.icpdas.com/faq/7188e/hardware/003.htm
• Firmware modifiable 
  We provide the Modbus SDK allowing users to develop their custom Modbus firmware.

If the default firmware doesn't totally suit your requirement. You can use Modbus SDK to modify the default firmware to add extra functions. The Modbus SDK has below features:

• Supports extra user-defined command protocol (TCP/IP) 
  Modbus/TCP protocol supports 2 basic data format (bit and 2-byte integer). It means if clients (or called masters) don't support Modbus/TCP or you need other format data (for example: string of floating value), I-7188E2 (with default firmware) cannot communicate with them. Using this feature, you can develop your special command protocol to transfer any format of data.
• Register based programming method (easy to use) 
  Modbus library supports 4 internal register tables (iMemory_AI, iMemory_AO, iMemory_DI, iMemory_DO), you can use these to store specific information. When Modbus/TCP clients request to I-7188E2-MTCP, Modbus kernel will response information from these 4 tables.
• Provides user-defined registers 
  The 4 internal register tables are all open to users. You need to assign these tables by yourself.
• Can link to Modbus/TCP slave devices
  By using function ModbusTCP_Master2Slave(declared in MBTCP_7E.h),the I-7188E2-MTCP can link 8 max . Modbus/TCP device.
• Can link to Modbus/RTU slave devices 
  By using function ModbusMaster2Slave (declared in MBTCP_7E.h), Modbus/RTU devices can be easily integrated to internal registers of I-7188E2-MTCP. An I-7188E2-MTCP polling every Modbus/RTU devices and put every necessary information to internal registers. Clients only ask the I-7188E2-MTCP to get all information of Modbus/RTU devices. That reduces loading of Clients.
• Can link to non-Modbus/RTU serial devices 
  Some serial devices don't support Modbus/RTU. We provide functions to let I-7188E2 -MTCP access serial devices. You can put information to internal registers of it. Thus, the non-Modbus serial devices can also support Modbus/TCP.
• Xserver SDK compatible 
  Modbus SDK is based on Xserver SDK. To lear more programming skills, you can refer demos of Xserver. To get information of demos of Xserver, please refer to CD:\Napdso\7188e\TCP\Xserver\Xserver.htm

We provide Modbus tools for Windows 98/SE/NT/2K/XP, it includes:

1. Modbus Utility
   • On-line configuration via Ethernet
   • On-line help
   • Automatically generate register mapping tables
   • Configuration export/imp
2. MBRTU 
   Modbus/RTU client (with source code in VB6) to diagnostic Modbus/RTU slave devices.
3. MBTCP 
   Modbus/TCP client (with source code in VB6) to diagnostic Modbus/TCP slave devices.