User`s manual
Table Of Contents
- 1. Introduction
- 2. Getting Started
- 3. Initial IP Address Configuration
- 4. Introducing Serial Port Operation Modes
- 5. Introducing OnCell Central and Ethernet Operation Modes
- 6. Using the Web Console
- 7. Cellular Network Settings
- 8. Configuring Serial Port Operation Modes
- 9. Configuring the Cellular-Enabling Ethernet Device
- 10. Configuring OnCell Central Management Software
- 11. Additional Serial Port Settings
- 12. System Management Settings
- 13. Software Installation/Configuration
- A. Pinouts and Cable Wiring
- B. RFC2217
- C. Dynamic Domain Name Server
- D. Well Known Port Numbers
- E. Auto IP Report Protocol
- F. GSM Alphabet
- G. Default Settings

OnCell G3111/G3151/G3211/G3251 Series User’s Manual Serial Port Operation Modes
4-5
Reverse Real COM Modes
The OnCell G3111/G3151/G3211/G3251 comes bundled with Moxa drivers for Windows
98/ME/NT/2000/XP/2003/2008/Vista systems and TTY drivers for Linux and Unix systems.
(For Windows systems, this option is only supported for Windows 2000, XP x86/x64, 2003
x86/x64, Vista x86/x64, and 2008 x86/x64.)
Reverse Real COM mode uses a mechanism similar to port mapping to enable your remote
device that is using a private IP address to remain accessible to external hosts. When this
mode is enabled, the Moxa driver that comes with the device establishes a transparent
connection from the device to the remote host by mapping the device’s serial port to a local
COM port on the remote host. Reverse Real COM mode supports up to 2 simultaneous
connections that enable serial devices to send data to 2 hosts simultaneously.
Types of Reverse Real COM Connection
1. Reverse RealCOM to PC’s IP address.
Most cellular service providers only provide customers with a dynamic private IP address,
which means that the OnCell G3111/G3151/G3211/G3251 will only obtain an IP address once
it is connected to the cellular network. Reverse RealCOM is a great feature that allows a PC
host to access an OnCell G3111/G3151/G3211/G3251 configured with a private IP address.