AT&T 3B2/300 Technical Reference Manual page 431

FUNCTIONAL D E S C R I P T I O N - - - - - - - - - - - - - - - - - - - - - - - - - - -
ID data is supplied to the bus when the AIC card is read (addresses OXOl and OX02). For addresses
OX04 and OXOS, the AIC Status Register information is passed to the bus. The following table contains
the AIC Status Register bit definitions.
BIT NAME DESCRIPTION
15 RESV151 WHEN 0, AIC FORCES DTR ACTIVE ON TRMl & TRM2
WHEN 1, DTR JS CONTROLLED BY THE 3B2 UART
14
--
RESERVED FOR FUTURE APPLICATIONS
13 --
RESERVED FOR FUTURE APPLICATIONS
12 -- RESERVED FOR FUTURE APPLICATIONS
11
-- RESERVED FOR FUTURE APPLICATIONS
10 TMOUTl WHEN SET, AN INTERRUPT ON FIRST TIMEOUT HAD OCCURRED
09 INSANEl WHEN SET, INDICATES SANITY TIMER HAS FIRED SECOND TIME
08 EXTTLll WHEN SET, INDICATES MINOR ALARM ON TTL INPUT 1
07 EXTTL21 WHEN SET, INDICATES MAJOR ALARM ON TTL INPUT 2
06 LOWBATl WHEN SET TO 1, INDICATES CLOSURE HAD OCCURRED ON
EXTERNAL "LOW BATTERY" INPUT FROM UPS
05 ACFAILl WHEN SET TO 1, INDICATES CLOSURE HAD OCCURRED ON
EXTERNAL "AC FAILURE" INPUT
04
INHALRMl
1 INDICATES ALL ALARM OUTPUTS INHIBITED
03 CLRTMRSO WILL BE ACTIVE O FOR 127.5 MILLISECONDS FOLLOWING A
CLEAR SANITY TIMER COMMAND
02 SANENl WHEN SET TO 1, SANITY TIMER ENABLED AND RUNNING
WHEN CLEARED, THE TIMER IS DISABLED
01 SWMAJORl 1 INDICATES SOFTWARE HAD SET MAJOR ALARM
00 SWMINORl 1 INDICATES SOFTWARE HAD SET MINOR ALARM
Dual Console
The dual console feature is basically a straight hardware type arrangement. The CONS port on the
AIC card is connected to the CONSOLE port of the computer. The leads are reversed on the CONS
port to allow the use of a standard 8-pin modular phone cord between the CONSOLE and CONS port.
The Data Carrier Detect (DCD) lines go high to determine which one of the TRM ports has data
flow. For example, when DCDl is high, only data from TRMl is allowed through the multiplexer.
The TRMl port has priority over the TRM2 port. That is, if both are ON (DCD high), TRMl data
will flow through the multiplexer and TRM2 will only mirror data received by TRMl. The following
table shows the remote console priorities based on DCD condition.
STATE OF DCD
SYSTEM BOARD ACTION
TRMl TRM2
TRMl TRM2 TRANSMIT RECEIVE
TRANSMIT
RECEIVE
OFF OFF NO
NO NO YES
ON
OFF YES YES NO NO
OFF ON NO NO
YES YES
ON ON YES YES YES NO
3-178 TECHNICAL REFERENCE MANUAL