LINKUP 5294 WITH DL5294 FIRMWARE
78
PADs are capable of echoing keycodes back to the terminal. If the PAD echoes the keycode
and the LinkUp 5294 also echoes the keycode, the result will be duplicate characters, as you can
see in Figure 8-3. Therefore, it is important to configure the PAD and the LinkUp 5294 properly.
Figure 8-3. Double Echo with PAD.
Figure 8-4 shows the flow of information between the keyboard, display, and the LinkUp 5294
when AID keys are pressed.
A =
Press the <CMD> key. The CMD 3 code goes to the LinkUp 5294.
B =
Recognizing the AID key, the LinkUp 5294 locks the keyboard.
C =
The CMD 3 code is sent to the host.
D =
The host processes the command. Then appropriate data and an unlock keyboard command is sent
to the LinkUp 5294.
E =
The LinkUp 5294 sends the data and a cursor positioning command to the display, and then unlocks
the keyboard.
Figure 8-4. AID Key Echo.
ON
SYS OK DCE
DTE
TXD
RXD
RTS
CTS
DTR
DSR
CD
RI/SYN
TXC
RXC
I/O FLT
CHANNEL ERROR
CH SEL
RESET
DataLynx /5294
TM
DataLynx
B
A
Host
Terminal
C
D
E
ON
SYS OK DCE
DTE
TXD
RXD
RTS
CTS
DTR
DSR
CD
RI/SYN
TXC
RXC
I/O FLT
CHANNEL ERROR
CH SEL
RESET
DataLynx /5294
TM
X.25
PDN
Terminal
PAD
Host
PAD
Terminal
DataLynx/5294
Host
D
C
B
A
LinkUp 5294
LinkUp 5294