User's Manual

3-2
sends a new data prompt out to the Base Station and the whole process begins
again.
A little more in depth…
This RF system’s dialogue is Terminal initiated. The Terminal says, “I’m here,
give me something to do. It is not designed for the Terminal to listen all day to see
if the host has something for it, unless the host sends out a message such as
“STAND BY, PRESS ENTER”. Then the Terminal will go to sleep and wake up
every few seconds to see if there is anything to do while displaying the message
“WAITING ON HOST PROMPT.” (After the terminal goes to sleep 8 times, it
only wakes up and asks every 16 seconds though.)
The Worth Data RF system is different from other systems in that our RF
Terminal does not constantly “listen” for a data prompt from the host. Other
systems are constantly waiting for a prompt from the host, using up valuable
battery life. We decided to use a different approach that would help to eliminate
unnecessary radio traffic, conserve battery power, and reduce the size of the
actual Terminal itself.
Here is how it works:
Each RF Terminal has a Terminal ID. When the RF Terminal powers up, it asks
if you want to SIGN ON? Pressing YES at the SIGN ON? prompt causes the
RF Terminal to transmit it’s Terminal ID and a byte of data indicating to the
Base Station that it wants to sign on to the system.
When the Base Station receives a SIGN ON message from a RF Terminal, the
Base Station transmits the SIGN ON information to the host computer. The host
computer application can then do one of two things:
1. If it has something for the Terminal to do, it can send a prompt to the Base,
which in turn transmits it to the Terminal. The RF Terminal receives the
prompt, waits for the operator to enter the requested data, and then
transmits the data back to the Base Station.
2. If the host program does nothing within an allotted time, the Terminal
displays the message:
WAITING ON HOST PROMPT
Lets suppose that a RF Terminal and a Base Station have been processing data by
sending prompts and data back and forth as described in example 1. The Base
Station sends a data prompt to the RF Terminal, the RF Terminal transmits the
operator-entered data back to the Base Station. If the host program has another
prompt for the terminal, the Base sends it out, repeating the process above.
Suppose the host program does not have a prompt ready to send back to the
Terminal; the Terminal transmits its data to the Base Station but does not