User`s manual

Table Of Contents
OnCell G3111/G3151/G3211/G3251 Series User’s Manual Serial Port Operation Modes
4-2
Overview
The OnCell G3111/G3151/G3211/G3251 cellular IP gateway enables traditional serial
(RS-232/422/485) devices for transmitting data over the cellular network. The IP gateway is a tiny
computer equipped with a CPU and TCP/IP protocols that can bi-directionally translate data
between the serial and IP formats. With the OnCell G3111/G3151/G3211/G3251, your computer
will be able to access, manage, and configure remote facilities and equipment over the cellular
network from anywhere in the world.
Traditional SCADA and data collection systems rely on serial ports to collect data from various
kinds of instruments. Since the OnCell G3111/G3151/G3211/G3251 cellular IP gateway
network-enables instruments equipped with an RS-232, RS-422, or RS-485 communication port,
your SCADA and data collection system will be able to access all instruments connected to a
standard TCP/IP network, regardless of whether the devices are used locally or at a remote site.
The OnCell G3111/G3151/G3211/G3251 is an external IP-based network device that allows you to
expand a serial port for a host computer on demand. As long as your host computer supports the
TCP/IP protocol, you will not be limited by the host computer’s bus limitation (such as ISA or
PCI), nor will you be limited if you do not have drivers for various operating systems.
In addition to providing socket access, the OnCell G3111/G3151/G3211/G3251 also comes with a
Real COM/TTY driver and a Reverse Real COM/TTY driver that transmits all serial signals intact.
This enables you to preserve your existing COM/TTY-based software without needing to invest in
additional software.
Three different socket modes are available: TCP Server, TCP Client, and UDP. The main
difference between the TCP and UDP protocols is that TCP guarantees delivery of data by
requiring the recipient to send an acknowledgement to the sender. UDP does not require this type
of verification, making it possible to offer faster delivery. UDP also allows you to unicast data to
one IP, or multicast the data to a group of IP addresses.