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Communication
The 7802 RF Terminal has two modes of communication:
•
Sign-In Mode
– the Terminal associates with an 802.11 access point and connects with your LAN. It
then attempts to link with a Connection Host or Web Application Server over the Internet and register
with an Application Server with matching username, password, and server ID. Upon receiving a “Sign-
In” signal from a Terminal, an Application Server will respond with either a prompt command or by
sending a batch mode program.
•
Site Survey Mode –
the Terminal scans the local RF environments and displays a report on what it finds.
Here is a discussion of the basic theory behind a
Two-Way
RF Terminal system in a little more depth...
This RF system’s dialogue is Terminal initiated. The Terminal says, “
I’m here, give me something to do
.
When you select
SIGN ON
the RF Terminal first establishes communication with the network as follows:
1.
It looks for an
Access Point.
If an SSID and/or security key (WEP/WPA) is set in the Terminal, the
Access Point must have matching settings. During this process, the terminal displays:
Initializing Radio Unit Please Wait...
2.
If the terminal is configured to obtain its IP address from a DHCP Server, it sends a request to the DHCP
server and displays:
DHCP Started Please Wait...
3.
The terminal requires an IP address or URL (web site address) setting for the Connection Host (see Wi-
Fi Setup). If a Connection Host and/or properly configured Application Server are not found, the
terminal will display:
Host Application Not Found
4.
If a connection Host and/or Application Server are found, the RF Terminal sends a SIGN ON message to
the Application Server.
When the Application Server (the WD7802term ActiveX control) receives a
SIGN ON
message from a
Terminal, the SIGN ON information is transferred to your application program through the
OnTermSignIn
event handler. The host application can then do one of three things:
1.
If it has something for the Terminal to do, it can send a prompt to the Terminal through a WD7802term
ActiveX control
Input
command. The RF Terminal receives the prompt, waits for the operator to enter
the requested data, and then transmits the data back to the application program.
2.
The Application Server can send a batch mode program to the Terminal so that data collection can
proceed without Internet connectivity.
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