Worth Data 7000 manual Control Keys for Possible Programming, Base Station Initialized Message

Automatic Check Back

When a terminal checks back in to see if there is a change in instructions, the host can send back the same prompt or send back a new prompt. The check back occurs according to the time specified in the Terminal's setup, (specified in increments of 5 seconds). When a check back occurs, the Terminal clears the screen of the current prompt, and sends back the following message:

Byte position	Function	Possible values
1	RF Terminal ID	0-9,A-Z,a-z,-=
2+	Check Back	BEL (ASCII 07)
Last	Termination of message	CR (ASCII 13)

Base Station Initialized Message

Whenever the Base Station is powered up, it sends a message back to the host as follows:

Byte position	Function	Possible values
1	BASE ID	* (Base ID is fixed)
2+	Base Initialization	DC3 (ASCII 19)
Last	Termination of message	CR (ASCII 13)

Since ASCII 19 is XOFF, the ASCII 19 character can be changed to ASCII 20 for XON/XOFF sensitive systems by changing the Base Station Setup. See Chapter 2; RF System Setup for details.

The Base Station Initialized message is provided so that the host will know that there has been a power interruption on the Base Station. When a serial device powers up, the first byte transmitted is often garbage. QBASIC handles the garbage character without incidence, but GWBASIC does not unless ON ERROR GOTO is used to trap the error. Be aware of this potential garbage-byte problem in your programming. To isolate and test for the problem, power up the Base without the serial cable connected. After you power the Base up, plug in the serial cable. You will not see the “Base Initialized” message but it should not matter when testing for the garbage data.

If a terminal is signed-on to the system, and the base station is re-initialized, the following message is sent to the terminal:

Base Reinitialized X Cycle Power on RF Terminal and Sign-on again to Restart_

where X is either a P (base initialization was power-related) or H (base initialization was host-related.

Control Keys for Possible Programming

There are some keys on the RF Terminal keypad that when pressed, can transmit special ASCII characters back to the host program. This feature might be used by a programmer to allow the operator to review transactions. You can use these keys for special program functions, such as scrolling thru data, backing up steps, jumping, finishing a process, etc The keys are as follows:

Key	Code transmitted to Host
UP ARROW key	FS (ASCII 28)
DOWN ARROW key	GS (ASCII 29)
LEFT ARROW key	RS (ASCII 30)
RIGHT ARROW key	US (ASCII 31)
BEGIN key	ETB (ASCII 23)
END key	CAN (ASCII 24)
SEARCH key	VT (ASCII 11)