User`s manual

Table Of Contents
OnCell G3111/G3151/G3211/G3251 Series User’s Manual Serial Port Operation Modes
8-5
Reverse Real COM Mode
TCP alive check time (default=7 min): This field specifies how long the OnCell
G3111/G3151/G3211/G3251 will wait for a response to “keep alive” packets before closing the
TCP connection. The OnCell G3111/G3151/G3211/G3251 checks the connection status by
sending periodic “keep alive” packets. If the remote host does not respond to the packet within the
time specified in this field, the OnCell G3111/G3151/G3211/G3251 will force the existing TCP
connection to close. For socket and device control modes, the OnCell G3111/G3151/G3211/G3251
will listen for another TCP connection from another host after closing the connection. If TCP alive
check time is set to 0, the TCP connection will remain open and will not send any “keep alive”
packets.
Max connection (default=1): This field is used if you need to receive data from different hosts
simultaneously. When set to 1, only one specific host can access this port of the OnCell
G3111/G3151/G3211/G3251, and the OnCell COM driver on that host will have full control over
the port. When set to 2, the specified number of hosts’ OnCell COM driver may open this port at
the same time. When multiple hosts’ OnCell COM driver open the port at the same time, the COM
driver only provides a pure data tunnel with no control ability. The serial port parameters will use
firmware settings instead of depending on your application program (AP).
Application software that is based on the COM driver will receive a driver response of “success”
when the software uses any of the Win32 API functions. The firmware will only send data back to
the driver on the host. Data will be sent first-in-first-out when data comes into the OnCell
G3111/G3151/G3211/G3251 from the Cellular or Ethernet interface.