User`s manual

Table Of Contents
OnCell G3111/G3151/G3211/G3251 Series User’s Manual Serial Port Operation Modes
8-18
Ethernet Modem Mode
The OnCell G3111/G3151/G3211/G3251 accepts the AT command ATD IP address:TCP port (for
example, ATD 192.168.127.1:4001) from the serial port and then requests a TCP connection from
the remote Ethernet Modem or PC. Here IP address is the IP address of the remote Ethernet modem
or PC, and TCP port is the TCP port number of the remote Ethernet modem or PC. Once the remote
unit accepts this TCP connection, the OnCell G3111/G3151/G3211/G3251 will send out the
CONNECT baudsignal via the serial port and then enter data 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 alivepackets before closing the TCP
connection. The OnCell G3111/G3151/G3211/G3251 checks connection status by sending periodic
keep alivepackets. 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 even if there is no response to the keep alive
packets.
TCP port (default=4001): This is the TCP port number assignment for the serial port on the OnCell
G3111/G3151/G3211/G3251. It is the port number that the serial port uses to listen to connections,
and that other devices must use to contact the serial port. To avoid conflicts with well known TCP
ports, the default is set to 4001.
Dial-in
The OnCell G3111/G3151/G3211/G3251 listens for a TCP/IP connection request from the remote
Ethernet modem or host. The OnCell G3111/G3151/G3211/G3251s response depends on the ATS0
value, as follows.
ATS0=0:
The OnCell G3111/G3151/G3211/G3251 will temporarily accept the TCP connection and then send
the RING signal out through the serial port. The serial controller must reply with ATA within 2.5
seconds to accept the connection request, after which the OnCell G3111/G3151/G3211/G3251
enters data mode. If no ATA command is received, the OnCell G3111/G3151/G3211/G3251 will
disconnect after sending three RING signals.