HP 2641A Reference Manual page 62

Data Communications
Table 5-8. Keyboard Interface PCA Strapping Options for Point-to-Point (Continued)
STRAP
S,T
U
v
W
x
y
STRAPPING OPTION
Main Channel Protocol
CPU Break
Carrier Detect
Data Comm Self Test
Enable
Data Speed Select
Ttansmit LED
NORMAL OPERATION
(SWITCH CLOSED)
Reverse Channel protocol (both
switches closed).
The CPU can interrupt the terminal
while it is in the transmit state. The
CPU initiates an ON to OFF transition
of the SB (122) (Secondary Receive
Data) line. The terminal responds by
turning off CA (106) (Request to Send)
and going to the receive state.
When the terminal is in the receive state,
an ON to OFF transition of CF (109)
(Carrier Detect) line from the modem
causes the terminal to go into the trans-
mit state. Transitions of CF have no
effect while the terminal is in the trans-
mit state.
Enables DATA COMM SELF TEST
from either the keyboard or escape
sequence.
Holds data speed signal low
(CH (111) =0).
The TRANSMIT light on the keyboard
is turned on when CB (106) (Clear to
Send) line from the modem is high. It is
turned off when the CB (106) line goes
low.
OPERATION WITH
STRAPPING OPTION
(SWITCH OPEN)
S-closed, T-open: Main channel with
STX/ETX as Start of Data and End of
Data.
S-open, T-closed: Main channel with
EOT as End of Data.
S-open, T-open: Main channel with
ETX as End of Data.
The terminal ignores all transitions on
the SB (122) (Secondary Receive Data)
line from the modem in the transmit
state.
Transitions of CF (109) (Carrier Detect)
line have no effect on the terminal.
Disables DATA COMM SELF TEST. If
self test is attempted (by either the key-
board or escape sequence), the test will
be aborted and ERROR 0 will appear
on the display.
Sets data speed signal high (CH (111)
=
1).
The TRANSMIT light on the keyboard
is turned on when the CC (107) (Data
Set Ready) line from the modem is high
and the 13260B Extended Asynchro-
nous Communications Interface PCA is
used. It is turned off when the CC line
goes low.
z
Parity
The PARITY switch on the terminal keyboard is affected as follows:
No Parity: Send 8 bits and receive 8
bits. Force bit 8 to zero. Check for
parity error.
Odd Parity: Send 7 data bits
+
odd
parity. Receive 7 data bits
+
odd
parity. Check for parity error.
Even Parity: Send 7 data bits
+
even
parity. Receive 7 data bits
+
even
parity. Check for parity error.
No Parity: Send 8 bits and receive 8
bits. Force bit 8 to one on send. No
check for parity error.
Odd Parity: Send 7 bits
+
odd parity.
Receive 7 bits. No check for parity error.
Even Parity: Send 7 data bits
+
even
parity. Receive 7 data bits. No check for
parity error.
5-15