IBM 2702 Information Manual page 39

Table 2 -6, CE Panel Indicators (Part 6 of 8)
Indicator
B-5
INTERFACE BUS IN
REO IN (Request In)
OP IN (Operation In)
ADR I N (Address In)
ST A I N (Status In)
SVC IN (Service In)
INTERFACE DATA
REGISTER C (0-7)
INTERFACE DATA
RE GI STE R D (0-7)
Roller C
BUFFER FIELD
(0-7)
CHAR ADR (Character
Address) 1, 2, and 4
COUNTER 1, 2,
4, and B
TIMEOUT 1 and 2
Definition
Nine indicators (B-5-2 to B-5-10). These indicate the Bus In lines between the 2703
and the channel.
One indicator (B-5-11). Active when any type service is requested by 2703 inter-
face controls. Indicated from the time the request is initiated until attachment to
the channe I .
One indicator (B-5-12). Indicates attachment to the channel for a Start I/O or
service cycle.
One indicator (B-5-13). Signifies that Address In tag is active on the interface.
One indicator (B-5-14). Signifies that Status In tag is active on the interface.
One indicator (B-5-15). Signifies that Service In tag is active on the interface.
Eight indicators (B-5-1B to B-5-25). Contains the third character within the group
of four transferred over the interface on a read or write type operation. I t also con-
tains the Sense Data byte during a Sense service cycle.
Eight indicators (B-5-26 to B-5-33). Contains the fourth character within the group
of four transferred over the interface on a read or write type operation. It also con-
tains the Status byte on a Status service cycle.
Eight indicators (C-1-0 to C-1-7). This field is used for assembly and disassembly of
low-speed characters, and for accumulating timeout counts. If BSC installed, this
field is used as a Buffer for BSC transmit characters and as a temporary storage for a
receive operation El B indication.
Three indicators (C-1-B to C-1-10). Defines during a read operation which of the
eight data-buffer slots the buffer field will be transferred to when a character has
been assembled. Similarly, during a write operation, the character address refers to
the ne'xt character to be taken from the data-buffer slots and placed in the buffer
field.
Four indicators (C-1-12 to C-1-15). The bit count is incremented as a bit is trans-
ferred between the Buffer Fie ld and the I ine base during read and write operations.
When this count reaches a specific value, depending on the terminal type, the data
in the Buffer Field is transferred to a data-buffer slot during a read operation or from
a data-buffer slot to the Buffer Field during a write operation. Used as Timeout field
for BSC lines.
Two indicators (C-1-16 and C-1-17). The timeout bits are set during a line timeout
and define the timeout condition occurring. Their bit configuration depends on the
terminal type and the mode in which the line is operating. For BSC lines, C-1-11
is also used for timeout definition.
Operations 2-23