If you send a standard "ping" (ICMP) packet to the LAN-Cell's public IP address (or DynDNS host name), the LAN-Cell will respond to the ping if it is configured to do so (the default) and your ISP does not filter ICMP traffic to or from the LAN-Cell.   This tells you that the LAN-Cell has connectivity to the Internet, but does not give you any information about devices attached to the LAN side of the LAN-Cell.

The LAN-Cell does not allow ICMP packets from the Internet to flow into the LAN.  Nor can you use the NAT/Port Forwarding feature to accomplish this because it supports only TCP and UDP packet types. 

To remotely test communications with your LAN devices you can either:

• Log into the LAN-Cell's SMT interface (Telnet/SSH) and go to the command line (Menu 24, 8).  Enter the command:
  IP PING aaa.bbb.ccc.ddd where aaa.bbb.ccc.ddd is the LAN IP address of your device.
  
  
• Use a TCP or UDP "ping" program to send packets to a port on your remote device.  You must setup the necessary NAT/Port Forwarding and Firewall rules to allow these types of packets to flow from the Internet to your LAN device.