IBM 2740-1 System Reference Manual page 36

Figure 21. IBM 2740 Model 2 Switch Panel
Receive Light. The Receive light (Figure 20), when
on, indicates the terminal is receiving and printing
incoming data. If the Buffered Receive special fea­
ture is installed, the light is on while data is being
received into the buffer and also during the buffer
printout.
NOTE: The Receive light blinks each tim e a
ch aracter is received.
Transmit Light. The Transmit light (Figure 20),
when on, indicates the terminal is transmitting data
from the buffer to the communications line.
NOTE: The Transmit light blinks each tim e a
ch aracter is tran sm itted .
Enter Light. The Enter light (Figure 20), turns
on whenever the Enter key is operated and remains
on until the Bid key or Reset key is operated.
on, the Enter light indicates that information entered
at the keyboard is being loaded into the buffer.
light will blink and the audible alarm will sound when
each of the last eight characters is entered into the
buffer, warning the operator that the buffer is nearly
filled (120, 248, or 440 positions).
is adjacent to the Enter key.
32
Bid Light. The Bid light (Figure 20), turns on when
the Bid key is operated indicating that the message in
the buffer is ready to be transmitted whenever the
terminal is polled by the CPU. The light turns off
when the terminal is polled and transmission begins.
The Bid light is adjacent to the Bid key.
Attn (Attention) Light. The Attention light (Figure
19), turns on and the audible alarm sounds momen­
tarily if the terminal is addressed while in enter,
local, or buffer-print status condition, or if the te r ­
minal typewriter is without paper. The Attention
light turns off when the condition that caused it to
turn on is corrected.
Platen Split Light (Special Feature). The Platen
Split light (Figure 19), is on whenever the platen is
in a split condition. This light may also glow (with
When
less brilliance) when the standard friction feed
platen is substituted for the split platen. See Split
The
Friction-Feed Platen under Special Features, Model
2 in this section of the manual.
Parity Light,. This light (Figure 21), turns on when­
The Enter light
ever the terminal receives or transmits a parity