Access control and security alarm apparatus and method

Access control and security alarm apparatus protects a building including a plurality of protection zones and an electrically locked door. The electrically locked door can be associated with any of the zones without re-wiring. Each zone can be operated to an autosecure condition wherein the zone, after being switched from a secure mode to an access mode to permit authorized entry, is automatically switched back to the secure mode without further action by the user. The apparatus can also be operated to a master reset mode wherein an alarm signal generated in response to activation of a sensor is immediately reset upon deactivation of the sensor to permit the system including each sensor to be conveniently tested by a single operator.

BACKGROUND 
The invention relates to access control and security alarm apparatus and, 
more particularly, to apparatus of this type in which a central station 
monitors a plurality of remote facilities. 
There is a continuing need to provide security and access control for 
commercial and residential buildings. Traditional methods using simple 
burglar alarms and uniformed security guards are becoming increasingly 
expensive and ineffective. 
A method which provides a high level of security at reasonable, cost uses a 
central station to monitor a number of remote locations which are 
connected to and communicate with the central station over telephone 
lines. An example of such a system is that described U.S. Pat. No. 
4,023,139 issued May 10, 1977 to Samburg. The system described in this 
patent is very effective in providing security at a reasonable cost by 
eliminating the need for uniformed security guards at each remote 
facility. 
Conventional security systems, however may suffer from the failure of users 
at the remote facilities to perform certain procedures. For example, users 
sometimes fail to reestablish the most secure condition of the system 
after requesting authorized entry to the protected area. 
This drawback can partially be overcome by increased vigilance on the part 
of central station monitoring personnel to detect such failures by the 
user. However, such measures have not been totally effective. Accordingly, 
an objective of the present invention is an access control and security 
alarm apparatus which maintains a high level of protection which requires 
a minimum of action by users at remote facilities. 
Since access control and security alarm systems are designed to provide 
security for both persons and property, such systems must be carefully 
installed and tested. Furthermore, to maintain a high level of protection 
and confidence in the system, periodic testing is desirable subsequent to 
installation. Each sensor must be tested upon installation and 
periodically thereafter to determine whether it is operating properly. 
Such testing is performed, for example, on door position sensors by 
opening the door or entry device and observing if an alarm signal is 
generated. After such an alarm signal occurs, then the system must be 
reset before testing the next sensor. Since for maximum security the reset 
control is not usually located near the sensors, at least two people are 
usually required to test the entire system. It is therefore a further 
objective of the present invention to reduce the cost and complexity of 
such testing. 
In prior art access control and security alarm systems having multiple 
protection zones, electrically locked doors operated in association with 
identification card readers were often used to provide controlled access 
by authorized persons to a specific protection zone. However, in such 
prior art systems, electrically locked doors and associated identification 
card readers were hard-wired into the systems such that the door and 
reader could only be associated with a single zone. In commercial 
buildings where tenants often desire to expand or modify their facilities, 
such hard-wired systems greatly limit the flexibility of users. It is 
therefore an additional objective of the invention to provide a 
multiple-zone access control and security alarm system which can easily 
associate an electrically locked door with any desired protection zone. 
In many buildings for which access control and security protection is 
desired, remotely operated access control systems are provided which 
include an electrically locked door and an entry authorization device such 
as an identification card reader or a numeric keypad. Such systems have 
been successfully integrated into prior art access control and security 
alarm systems by wiring the remotely operated access control system to the 
associated protection zones. Thus, the system was fixedly associated with 
that zone such that violation of the security of the system would cause an 
alarm for its associated zone only. This limited flexibility of the entire 
system, and, once installed, prevents the remotely operated access control 
system from being easily integrated into another protection zone. 
Accordingly, it is an objective of the present invention to provide an 
access control and security alarm system having a plurality of protection 
zones and a plurality of remotely operated access control systems which 
can be simply and conveniently configured to associate any remotely 
operated access control system with any protection zone. 
SUMMARY OF THE INVENTION 
The present invention provides an access control and security alarm 
apparatus including a central station having a host computer connected to 
a plurality of remote locations by a communication channel. The remote 
locations are typically buildings located at distances of up to 1500 miles 
from the central location. Each remote station includes one or more master 
control devices, each connected to a number of input and output devices. 
Each master control device provides access control and security alarm 
functions for a plurality of protection zones. 
A remote location typically consists of a commercial office building having 
a main entrance and lobby serving a number of separate office suites. Each 
office suite may be occupied by a separate tenant in the building and may 
constitute a separate protection zone served by a master control device. 
Input devices to the master control device include one or more condition 
sensors for each zone connected in a loop to two terminals of the master 
control device. Such sensors may be any generally known type of normally 
closed switch contacts mounted, for example, in doors or windows such that 
the switch contacts open when the associated door or window is opened. 
Other input devices may include a tamper circuit consisting of a series 
circuit through the various components of the remote station such that 
unauthorized modification or removal of any of the security equipment will 
cause an open circuit in the tamper loop which will, in turn, generate an 
alarm condition in the master control device. An access/secure key switch 
is also provided for each protection zone for setting each zone in either 
an access condition permitting entry through doors in the protection zone 
without generating an alarm signal or a secure condition in which alarms 
will be generated by entry into the zone. 
Each master control device may also have associated with it a plurality of 
authorized entry devices such as numeric keypads or identification card 
readers. These devices are usually placed in proximity to a door having an 
electrically operated lock which normally maintains the door in a locked 
condition. An authorized user must enter a specified numeric key sequence 
into a numeric keypad or insert a properly coded identification card into 
the card reader to obtain entry. Signals are passed from the keypad or 
card reader to the master control device and transmitted over the 
communication channel to the host computer. If the identification card is 
determined by a computer at the host location to represent an authorized 
user for the current time and location, the host computer sends a signal 
back over the communication channel to the master control device which 
then unlocks the electrically operated lock and permits the authorized 
user to pass through the door. Each master control device also generally 
includes exit push-button switches for protection zones having 
electrically locked doors located inside the door to permit the door to be 
opened without a card. 
Output devices for each master control device include, in addition to the 
control signals for the electrically operated lock, a control panel having 
a plurality of indicator lights which signal the status of the master 
control device and the various protection zones served by the master 
control device, and a plurality of sirens or other alarm indicators, one 
for each zone. 
In order for an alarm signal to be generated in a protection zone, three 
conditions must be present. First, the zone must be placed in the arm mode 
by a signal from the central station. Second, the user at the remote 
location must operate his zone from the access mode to the secure mode by 
operating an access/ secure key switch. At this point, the protection zone 
is armed and secured such that the third condition, which is a subsequent 
entry through a door or window protected by a sensor connected to the 
master control device, will cause an alarm signal to be generated. Once 
such an alarm occurs, it can only be reset by one of the following 
actions: (1) activation of a reset switch at the master control device, 
(2) an authorized entry generated either by a proper identification card 
or numeric keypad entry, (3) activation of the entry switch at the 
appropriate authorized entry device, (4) putting zone in access mode, or 
(5) receipt of a reset signal from central station. It is to be noted that 
removal of the third condition for alarm signal generation, such as 
closing the door which activated a sensor, will not result in a reset 
condition and the alarm signal will continue to be generated. 
The present invention achieves the desired objectives by providing an 
access control and security alarm apparatus which permits a single 
operator to effectively test each sensor by placing the apparatus in a 
"master reset" mode, sequentially testing each sensor by producing the 
condition it was desired to detect (such as opening a door), and observing 
the production of an appropriate alarm signal. Removal of the condition 
(that is, closing of the door) when the system is in the master reset mode 
will cause the immediate deactivation of the alarm signal. The next sensor 
is then tested by producing the condition it was designed to detect and 
observing the production of an associated alarm signal. Removal of the 
detected condition will also cause cessation of the alarm signal. In a 
similar manner, each sensor served by a master control device can be 
easily tested by a single maintenance person without the need to return to 
the master control station to provide a reset of the generated alarm 
condition, as was required in apparatus of prior art. 
The present invention also provides maximum security with increased 
convenience to the user through an "autosecure" mode. As in previous 
systems, generation of an alarm signal requires that two conditions be 
present before activation of a sensor will cause an alarm signal. First, 
the zone must be placed in an armed condition by the generation of an arm 
signal from the central station to the specified protection zone. Second, 
the user at this zone must operate the zone to a secure mode through 
activation of a key switch. Activation of any sensor following these two 
actions will result in the production of an alarm signal. 
If it is desired to enter the protection zone when the zone is both armed 
and secure, it is necessary for the user to once again activate the key 
switch to place the zone in the access mode. Entry through a protected 
door can thus be achieved without the generation of an alarm signal. 
However, in order to return the zone to its condition of greater security, 
the user must remember to once again activate the key switch to place the 
zone in the secure mode. The present invention provides that the central 
station may generate an autosecure signal which, when transmitted to the 
master control device at the remote location, places a specified zone in a 
secure and an autosecure mode. The autosecure mode specifies that when the 
user activates the key switch to place the zone in the access mode and 
enters through a door, the master control device will automatically return 
the zone to the secure mode after expiration of a predetermined delay 
period, such as 30 seconds. In the event the door is still open at the 
time of expiration of the delay period, the master control device will 
place the zone into the secure mode only at such time as the door is once 
again returned to the closed position. Similarly, if a door is open when 
the autosecure command is received by the master control device for this 
zone from the central station, the zone is placed in the secure mode only 
when the door is closed. In this manner, maximum security can be 
maintained for the zone with minimum inconvenience to the user. 
To achieve the objects and in accordance with the purpose of the invention 
as embodied and broadly described herein, an access control and security 
alarm apparatus comprises a plurality of sensors activated in response to 
a predetermined condition, an alarm indicator, and control means for 
activating the alarm indicator upon activation of at least one of the 
sensors. The invention also includes a master reset input device for 
selectively placing the control means in a normal mode wherein an 
activated alarm indicator remains activated independent of the condition 
of the sensors, and a master reset mode wherein the control means 
deactivates the alarm indicator whenever all of the sensors are 
deactivated. 
The control means is also operative to selectively place the apparatus in 
an access mode preventing production of an alarm signal or a secure mode 
wherein activation of one or more sensors will result in the production of 
an alarm signal. The control means is responsive to an input signal to 
place the system in an autosecure mode in which the apparatus is 
immediately placed in a secure mode if none of the sensors are activated 
and is placed in the secure mode only when all sensors are inactive if one 
or more sensors are activated at the time of receipt of the autosecure 
signal. When the apparatus is in the autosecure mode, the control means 
returns the apparatus to the secure mode a predetermined time after the 
apparatus is placed in the access mode if none of the sensors are 
activated at that time or if the zone is disarmed. If one or more sensors 
was still activated at the expiration of the predetermined time period, 
the zone will be placed in the secure mode when all of the sensors become 
deactivated. 
The accompanying drawings which are incorporated in and constitute a part 
of the specification, illustrate an embodiment of the invention and, 
together with the description, serve to explain the principles of the 
invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring to the figures, like reference characters refer to corresponding 
elements. FIG. 1 shows an access control and security alarm system 10 
which is a preferred embodiment of the present invention. 
The physical apparatus in system 10 will first be described, followed by a 
description of the operation of the system. Finally, a detailed 
description will be provided of the logic embodied in instructions 
contained within microcomputer memory of each master control device 16. 
Apparatus Description 
The system 10 includes a central station 12 which has a host computer 13 
serving as a central monitoring point for a plurality of remote stations 
14. The remote stations 14 are typically in multiple-tenant residential or 
commercial buildings located remote from the central station 12. Each 
remote station 14 includes one or more master control devices 16 which 
provide access control and security alarm functions for up to thirty-two 
separate protection zones. Each master control device 16 has connected 
thereto a plurality of input devices 18 and a plurality of output devices 
20. Furthermore, each master control device 16 may have up to four 
remotely operated access control systems 22 each consisting of an entry 
authorization device such as a numeric keypad or identification card 
reader, an electrically operated lock, a lock sense contact, and a door 
position indicator. These entry authorization devices are well known in 
the art. For example, numeric keypad entry stations may be a type 7023 
obtainable in commercial quantities from the Corby Corporation and the 
identification card readers may be a type SAS-3 obtainable in commercial 
quantities from the Sensor Engineering Corporation. For convenience, the 
term "card reader" will be used instead of "entry authorization device" 
but it is to be understood that this term also includes numeric keypad 
entry authorization devices. 
Each remote station 14 is connected to the central station 12 by means of a 
communication channel which in the preferred embodiment consists of a pair 
of telephone lines 24 and 26. The telephone line 24 transmits data from 
the central station to the first master control device 16 of the remote 
station 14. Each master control device 16 at the remote station is 
connected to the next master control device by a communication line 28 
consisting of a single twisted pair line. The output of the last master 
control device at the remote station 14 is connected to and transmits data 
over the telephone line 26 to the central station. 
A normally closed communication bypass relay 23 is connected in parallel 
with each master control device 16 on the communication lines 24, 26 and 
28. When the associated master control device 16 is operated normally, the 
relays 23 are energized to an open-circuit position. However, if a failure 
should occur in the master control device 16, the relay 23 is deenergized 
to return to its closed position and shunt the inoperative master control 
device 16. 
Each master control device 16 is conceptually separated into four reader 
interface modules (RIMs), each of which can have associated therewith a 
single remotely operated access control system 22. Each RIM can further 
have a maximum of 8 protection zones associated therewith. Thus, each 
master control device 16 can have up to four remotely operated access 
control systems 22 and thirty-two protection zones. 
FIG. 2 shows input and output devices 18 and 20 for each RIM appearing on 
the panel of each master control device 16. A plurality of arm LEDs 30 is 
provided, one for each zone. When the host computer 13 sends an arm signal 
to a specific zone of a remote station 14, the appropriate LED 30 will be 
energized. Similarly, reset, autosecure, and alarm LEDs 32, 34, 36, 
respectively, are also provided on the panel of each master control device 
16. 
The reset LEDs 32 for each zone are energized whenever the host computer 
transmits a reset signal to the specific zone. In addition, all reset LEDs 
32 are energized whenever master reset is called for by personnel at the 
remote station 14. The autosecure LEDs 34 are energized for each zone to 
which the host 13 has transmitted an autosecure signal. The alarm LEDs 36 
are energized for each zone in which an alarm signal has been generated as 
a result of activation of a sensor within that zone. Other output devices 
20 include alarm indicators such as sirens or warning bells. 
Also present on the panel of each master control device 16 is a local arm 
push-button 38, a local arm LED 40, a siren disable push-button 42, a 
siren disable LED 44, a master reset pushbutton 46, and a master reset LED 
48. Security or maintenance personnel at the remote station 14 can provide 
a local arm signal for all zones at the remote station 14 in place of an 
arm signal supplied by the central station 12. Indication of such action 
is provided by energization of the local arm LED 40. Such personnel can 
also provide a siren disable function for various maintenance purposes by 
activating the siren disable push-button 42, an indication of which is 
provided by energization of the siren disable LED 44. Finally, personnel 
at the remote station 14 can also provide a master reset function for all 
zones controlled by the master control device 16 by operating the master 
reset push-button 46, an indication of which is provided by energization 
of the master reset LED 48. 
Referring now to FIG. 3, there is shown a schematic diagram of a terminal 
strip for a single RIM of a master control device 16 to which external 
input and output devices 18 and 20 are connected. A separate tamper loop 
50 is connected for each zone to indicate unauthorized removal or 
alteration of equipment associated with the zone. As can be seen in FIG. 
3, the tamper loop consists of a series circuit which extends through 
various components associated with the master control device 16 such as 
button switches located behind key-switch plates and on control instrument 
doors, and a tamper loop conductor running through all security cables. 
A separate door loop 52 for each zone, each consisting of a plurality of 
sensors 53, is also connected to the terminals of the master control 
device 16. The sensors 53 can be any type of normally closed contact 
closure device known in the art which activates in response to occurrence 
of a specified condition. Typically, the sensors 53 consist of contacts 
which are closed when an associated entry device such as a door or window 
is also closed. When the associated entry device opens, the contacts of 
the sensor 53 also open. Other types of sensors 53 may also be included in 
the door loop such as floor pressure pads, ultrasonic motion detectors, 
and infrared detectors. Since the sensors 53 are connected in series, 
activation of any of the sensors will be detected as an open circuit in 
the door loop 52. 
Door power terminals 54 are provided to control an electrically operated 
lock of a remotely operated access control system 22. Each master control 
device 16 can control up to four such systems 22, one for each RIM. As can 
be seen in FIG. 3, the door power terminals 54 are connected in series 
with the operating coil of a relay 56, the energization of which closes 
the contacts of the relay 56 to energize a solenoid 58 by a power source 
60. The solenoid 58, in turn, operates a lock bolt 62 to either lock or 
unlock a door. Although the position of the bolt 62 can be either normally 
closed or normally open such that energization of the solenoid 58 results 
in either opening or closing, respectively, of the bolt 62, in the 
preferred embodiment, the bolt 62 is of the normally open type. Thus, 
energization of the solenoid 58 caused by activation of the door power 
terminal 54 will lock the associated door. In this manner, emergency 
conditions such as a power failure or fire will not be able to lock the 
door and possibly trap occupants of the protected zone. Also associated 
with the door power terminals 54 is a lock sense terminal 64. Lock sense 
terminal 64 detects the energization of the solenoid 58 to provide 
feedback to the master control device 16 of the activation of the door 
power terminals 54. 
Further associated with the door power terminals 54 and lock sense terminal 
64 is a door position indicator 66. The indicator 66 can be identical to 
sensors 53 to provide an indication of the position of the door associated 
with the electrically operated lock which is controlled and sensed by the 
terminals 54 and 64, respectively. Exit and entry switches 68 and 70, 
respectively, may be provided to enable users in a protected zone to 
operate the electric door lock. Although both the exit switch 68 and the 
entry switch 70 are contact closure devices, the exit switch 68 is a 
momentary contact push-button while the entry switch 70 is a mometary 
contact key-operated switch. Thus, the exit switch 68 can be operated by 
anyone, whereas the entry switch 70 is restricted to persons having 
possession of a key. The reason for this is that activation of the exit 
switch 68 serves only to unlock the electrically operated lock associated 
therewith, whereas activation of the entry switch 70 will result in reset 
of an existing alarm condition in a manner to be described more completely 
below. 
A card reader 21 is also associated with the electrically operated lock, 
door power terminals 54, lock sense terminal 64, and door position 
indicator 66. Inputs from the card reader 21 to the master control device 
16 include both data and control inputs in a manner well known in the art. 
A key switch 72 is provided for each zone to enable a user to operate the 
zone between an access mode wherein activation of any of the sensors 53 
will be ignored and a secure mode wherein activation of a sensor 53 will 
result in the generation of an alarm condition (assuming that the zone is 
armed by the central station 12). A secure light 74 is provided for each 
zone to indicate when the zone is in the secure mode. 
A dual in-line package (DIP) switch 55 having five contacts is shown in 
FIG. 3. Four such switches 55 are located in the master control device 16, 
one for each RIM. Each switch 55 is used to set the value of logical 
variables ZD1, ZD2, ZD3, QD1, and QD2 for the associated RIM to specify to 
which of the 32 protective zones served by the master control device 16 
each remotely operated access control system 22 is coupled. 
Referring now to FIG. 4, there is shown a schematic block diagram of the 
master control device 16. As can be seen therein, each master control 
device 16 includes control logic 78 which, in the preferred embodiment, 
comprises a microcomputer central processing unit such as a type 8085 
obtainable in commercial quantities from the Intel Corporation. Connected 
between the control logic 78 and the input devices 18, output devices 20, 
and card readers 21 is an input/output interface circuit 80. Although the 
input/output interface circuit 80 is indicated as a single block, in the 
preferred embodiment, the actual function of the block 80 is performed by 
a plurality of buffer and driver circuits in a manner well known to those 
skilled in the art. 
Connected between the control logic 78 and the input telephone line 24 and 
connecting line 28 is a communication interface 83 which, in the preferred 
embodiment, comprises a universal asynchronous receiver transmitter 
(UART). Also connected to the control logic 78 are a timer 85, program 
memory 87, RAM memory 89 and a power supply 90. The components 78, 80, 83, 
85, 87, 89, and 90 of the master control device 16 are electrically 
connected in a conventional manner as is well known by those skilled in 
the art. 
In accordance with the present invention, control means are provided for 
activating the alarm indicator upon activation of at least one of the 
sensors. As embodied herein, the control means comprises control logic 78, 
RAM memory 89, and program instructions contained in program memory 87. 
The master control device 16 performs its function by analyzing the 
condition of logical input variables received from the host computer 13 of 
the central station 12 and from input devices 18 and by generating a 
plurality of logical output variables for transmission to the host 
computer 13 and the output devices 20. The status of the aforementioned 
logical variables is maintained in memory locations organized as storage 
buffers of RAM memory 88. A schematic diagram of these buffers is shown in 
FIG. 5. As can be seen therein, the buffers comprise a plurality of host 
input buffers 82, host output buffers 84, external input buffers 86, and 
external output buffers 88. A separate buffer 82, 84, 86 and 88 is 
provided for each of the four RIMs contained in each master control device 
16. In addition, each of the buffers 82, 84, 86, and 88 includes a 
corresponding identical buffer 82a, 84a, 86a and 88a which is used to 
detect a change in condition of the contents of the buffers in a manner to 
be more completely described below. 
Each of the buffers 82, 84, 86 and 88 has stored therein a plurality of 
values corresponding to the status of logical variables. Each of the 
buffers 82, 84, 86 and 88 includes a maximum of 48 logical variables 
organized in eight groups of six each. In many cases, the eight groups 
correspond to the eight protection zones which are associated with each 
RIM. The value of each logical variable is either "active" or "restored." 
The specific logical variables stored in the buffers 82, 84, 86 and 88 are 
shown in Tables I, II, III and IV, respectively. 
The status of the logical variables of the external input buffer 86 
represents the actual physical status of an input device 18. The manner in 
which the physical status (open circuit, closed circuit, presence of 
voltage, absence of voltage, etc.) is transferred to a logical variable is 
dependent upon the specific type of control logic 78 and input/output 
interface 80 which are provided. In any case, this process is well known 
to those skilled in the art and will not be described in detail. 
Similarly, the manner in which a logical variable in external output 
buffer 86 is used to operate a physical device such as a solenoid or siren 
is well known to those skilled in the art and will not be described in 
detail. 
TABLE I 
__________________________________________________________________________ 
HOST INPUT BUFFER 82 
GROUP 
POINT 
(ZONE) 
1 2 3 4 5 6 
__________________________________________________________________________ 
1 PROP ALARM1 
ACCESS1 
TAMPER1 
CONTACT1 
2 ALARM2 
ACCESS2 
TAMPER2 
CONTACT2 
3 ALARM3 
ACCESS3 
TAMPER3 
CONTACT3 
4 ALARM4 
ACCESS4 
TAMPER4 
CONTACT4 
AC POWER 
5 LOCAL ARM ALARM5 
ACCESS5 
TAMPER5 
CONTACT5 
BAT. SUPV 
6 SIREN DISABLE 
ALARM6 
ACCESS6 
TAMPER6 
CONTACT6 
GROUND 
7 MASTER RESET 
ALARM7 
ACCESS7 
TAMPER7 
CONTACT7 
BOX TAMPER 
8 PERIM. PROP 
ALARM8 
ACCESS8 
TAMPER8 
CONTACT8 
SIREN POWER 
__________________________________________________________________________ 
These logical variables are transmitted to the host computer 13 to inform 
the host of the status of the input devices 18 connected to the master 
control device 16. 
PROP Activates 30 seconds after LOCK SENSE (defined in Table III) 
restores (bolt unlocks). Restores when LOCK SENSE activates. 
LOCAL ARM Toggles when LAPB (Table III) activates (pushbutton pressed) o 
toggles when LA OUTPUT activates. 
SIREN DISABLE Toggles when SDPB (Table III) or SD OUTPUT (Table II) 
activates. 
MASTER RESET Toggles when MRPB (Table III) or MR OUTPUT (Table II) 
activates. 
PERIMETER PROP Activates 30 seconds after PERIMETER LOOP (Table III) 
restores (door opens). Restores when PERIMETER LOOP activates. 
TABLE II 
__________________________________________________________________________ 
HOST OUTPUT BUFFER 84 
GROUP 
POINT 
(ZONE) 
1 2 3 4 5 6 
__________________________________________________________________________ 
1 DOOR CTL ARM1 
RESET1 
AUTOSECURE1 
2 ARM2 
RESET2 
AUTOSECURE2 
3 ARM3 
RESET3 
AUTOSECURE3 
4 ARM4 
RESET4 
AUTOSECURE4 
5 LOCAL ARM OUT 
ARM5 
RESET5 
AUTOSECURE5 
6 SIREN DISABLE OUT 
ARM6 
RESET6 
AUTOSECURE6 
7 MASTER RESET OUT 
ARM7 
RESET7 
AUTOSECURE7 
8 ARM8 
RESET8 
AUTOSECURE8 
__________________________________________________________________________ 
These logical variables are transmitted to the master control device 16 
from the host computer 13 and direct the master control device 16 to 
perform the designated actions with regard to the zones of the associated 
RIM and the associated output devices 20. 
DOOR CTL When activated, indicates that the electrically operated lock 
for this RIM is to be locked. 
LA OUTPUT When activated, indicates that the local arm LED 40 for this 
RIM is to be energized. 
SD OUTPUT When activated, indicates that the siren disable LED 44 for 
this RIM is to be energized. 
MR OUTPUT When activated, indicates that the master reset LED 48 for thi 
RIM is to be energized. 
ARMz (zone number) When activated indicates that this zone number should 
be placed in the arm mode. 
RESETz (zone number) When activated, indicates that this zone number 
should be reset. 
AUTOSECUREz (zone number) When activated, indicates that this zone shoul 
be placed in autosecure mode. 
TABLE III 
__________________________________________________________________________ 
EXTERNAL INPUT BUFFER 86 
__________________________________________________________________________ 
GROUP 
POINT 
(ZONE) 
1 2 3 4 5 6 
__________________________________________________________________________ 
1 LOCKSENSE DOOR LOOP 1 
TAMPER LOOP 1 
KEYSWITCH 1 
CTI1 
ZD1 
2 DOOR POS DOOR LOOP 2 
TAMPER LOOP 2 
KEYSWITCH 2 
CTI2 
ZD2 
3 EXIT DOOR LOOP 3 
TAMPER LOOP 3 
KEYSWITCH 3 
CTI3 
ZD3 
4 ENTRY DOOR LOOP 4 
TAMPER LOOP 4 
KEYSWITCH 4 
CTI4 
(AC SENSE) QD1 
5 LOCAL ARM PB 
DOOR LOOP 5 
TAMPER LOOP 5 
KEYSWITCH 5 
CTI5 
(BAT. CHG) QD2 
6 SIREN DISABLE PB 
DOOR LOOP 6 
TAMPER LOOP 6 
KEYSWITCH 6 
CTI6 
GROUND DETECT 
7 MASTER RESET PB 
DOOR LOOP 7 
TAMPER LOOP 7 
KEYSWITCH 7 
CTI7 
BOX DOOR LOOP 
8 PERIM. LOOP DOOR LOOP 8 
TAMPER LOOP 8 
KEYSWITCH 8 
CTI8 
SIREN 
__________________________________________________________________________ 
POWER 
These logical variables represent status of signals received from input 
devices 18 for this RIM. 
LOCK SENSE - When activated, indicates that power has been applied to 
solenoid 58 of the electrically operated lock for this RIM. 
DOOR POS - This is the condition of sensor 66. When activated, indicates 
that the door associated with the electrically operated lock for this RIM 
is open. 
EXIT - This is the status of exit switch 68 associated with the 
electrically operated lock for this RIM. When activated, indicates that 
the switch 68 closed. 
ENTRY - When activated, indicates that the switch 70 is closed. 
LAPB - When activated, indicates that the local arm push-button 38 for 
this RIM has been pressed. 
SDPB - When activated, indicates that the siren disable push-button 42 
for this RIM has been pressed. 
MRPB - When activated, indicates that the master reset puch-button 46 for 
this RIM has been pressed. 
PERIMETER LOOP - When activated, indicates that one of the sensors 53 of 
the parameter loop 51 has been activated. 
DOOR LOOPz (zone number) - When activated, indicates that one of the 
sensors 53 of the door loop for this zone has been activated. 
TAMPER LOOPz (zone number) - When activated, indicates that the series 
circuit of the tamper loop 50 for this zone has been broken. 
KEYSWITCHz (zone number) - When activated, indicates that the keyswitch 
72 has been activated to toggle this zone between access mode and secure 
mode. 
CTIz (zone number) - When activated, indicates that an auxiliary contact 
input has been activated. This input is used for various miscellaneous 
purposes such as to provide access to a janitor's door. 
ZD 1, ZD 2, ZD 3, QD 1, QD 2 - Each master control device 16 can handle 
up to four PIMs, and each RIM can serve a single remotely operated access 
control system and up to eight zones, providing a total capacity for each 
master control device 16 of 32 zones. The zone circuitry in the master 
control device 16 is provided on four 8-zone modules. The quantities QD 1 
and QD 2 constitute a 2-bit number designating which of the four zone 
module boards contains the zone to which a remotely operated access 
control system for this RIM is interfaced. The quantities ZD 1- ZD 3 
constitute a 3-bit number designating to which zone of the 8-zone module 
designated by QD 1- QD 2, the remotely operated access control system is 
interfaced. 
AC SENSE - When activated, indicates that AC power is available. 
BATTERY CHG - When active, indicates that the battery of power supply 90 
is charging. 
GROUND DETECT - When active, indicates that a ground fault has occurred 
on this RIM. 
BOX DOOR LOOP - When active, indicates that the door to the mounting box 
for this master control device is open. 
SIREN PWR MON - When active, indicates that no power is available to 
energize the siren for this RIM. 
TABLE IV 
__________________________________________________________________________ 
EXTERNAL OUTPUT BUFFER 88 
GROUP 
POINT 
(ZONE) 
1 2 3 4 5 6 
__________________________________________________________________________ 
1 DOOR PWR SIREN1 
SECURE1 
ARM1 
RESET1 
AUTOSECURE1 
2 SIREN2 
SECURE2 
ARM2 
RESET2 
AUTOSECURE2 
3 SIREN3 
SECURE3 
ARM3 
RESET3 
AUTOSECURE3 
4 SIREN4 
SECURE4 
ARM4 
RESET4 
AUTOSECURE4 
5 LOCAL ARM SIREN5 
SECURE5 
ARM5 
RESET5 
AUTOSECURE5 
6 SIREN DISABLE 
SIREN6 
SECURE6 
ARM6 
RESET6 
AUTOSECURE6 
7 MASTER RESET 
SIREN7 
SECURE7 
ARM7 
RESET7 
AUTOSECURE7 
8 SIREN8 
SECURE8 
ARM8 
RESET8 
AUTOSECURE8 
__________________________________________________________________________ 
These logical variables represent output control signals for the output 
devices 20 associated with this RIM. 
DOOR PWR Interrupts power to solenoid 56 when DOOR CTL is active. 
LOCAL ARM When active, energizes local arm LED 40. 
SIREN DISABLE LED SD LED 44 lights whenever SIREN DISABLE is active. 
MASTER RESET LED MR LED 48 lights whenever MASTER RESET is active. 
SIRENz (zone number) Active whenever ALARMz or TAMPERz is active and 
SIREN DISABLE is restored. Restores in 5 minutes or earlier if 
ALARM/TAMPERz restores activates siren for this zone. 
ACCESSz Lights the access LED 74 on the keyplate for the zone. Active 
whenever ACCESSz is restored (zone in secure). 
ARM LEDz Arm LED 38 for this zone lights whenever zone is armed: ARMz 
active or LOCAL ARM active. 
RESET LEDz Reset LED 33 for this zone lights whenever RESETz is active o 
MASTER RESET is active. 
Functional Description 
The functional description of the system will now be provided from the 
point of view of a user. As stated previously, a remote station 14 is 
typically located at a multiple tenant building containing a number of 
apartments or office suites. The master control device 16 is typically 
located in a maintenance area or utility room to provide protection for 
the building in general and a plurality of separate office suites. The 
position of the main entrance door for the building is monitored by a 
sensor 53 (FIG. 3) connected in the perimeter loop 51. Normal entry and 
exit through this door will not result in any indication either locally or 
at the central station 12. However, if the main entrance door remains open 
for more than 30 seconds, this fact is transmitted to the central station 
12 by activation of the PERIMETER PROP logical variable in the host input 
buffer 82. Opening of the door for more than 30 seconds is a condition of 
which the central station 12 should be aware, since it could conceivably 
represent a loss of access control. 
When the tenants of the office suite leave the office at the end of the 
day, the doors are locked and the zone associated with the office suite 
switched to the secure mode by operation of the keyswitch 72. A light 74 
usually located in close proximity to the keyswitch 72 to indicate secure 
mode is then lighted. 
An alarm cannot yet be generated in the zone, however, since the zone has 
not yet been armed by a signal from the central station 12. This is to 
allow the suite to be cleaned at the end of the day. Cleaning personnel 
are provided with a key to the suite to permit them to enter to clean the 
premises. When cleaning is completed, a telephone call is placed to the 
central station 12 informing of this fact. The central station then sends 
an arm signal to the zone. When this signal is received, the zone is in 
condition to generate an alarm upon detection of an unauthorized entry. In 
the event that the telephone call is not placed to the central station 12 
requesting that the zone be armed, personnel at the central station may 
follow a procedure in which the arm signal is sent at a specified time, 
regardless of whether a telephone request has been received. 
With the zone both armed and secured, entry into the zone which activates 
any of the sensors 53 of the zone door loop will cause an alarm to be 
generated and transmitted to the central station, and will also cause the 
siren associated with the zone to sound. The siren will continue until the 
zone is reset by a signal from the central station 12. Alternatively, the 
siren can be silenced by switching the zone to access or by an authorized 
entry which activates the ENTRY logical variable for this RIM. Entry can 
be activated through the use of the keyswitch 72 or by use of a card 
reader 21 associated with this zone. It must be emphasized that not all 
zones have a card reader associated therewith. Each master control device 
16 can handle a maximum of four card readers, whereas up to 32 zones may 
be protected by a single master control device. 
In prior art systems, if entry is desired to a zone in both arm and secure 
modes, a user would activate the key switch 72 to return the zone to the 
access mode, to permit entry without generation of an alarm. It was then 
required that the zone be manually returned to the secure mode. Often, 
users would forget to return the zone to the secure mode, resulting in a 
lower level of security. The present invention provides increased 
convenience for the user as well as increased security by providing an 
autosecure mode. 
In accordance with the invention, control means are provided which are 
connected to the sensors and to the alarm indicators for responding to 
control signals by placing a specific zone into an access mode preventing 
activation of the alarm indicator upon activation of the sensors or into a 
secure mode wherein activation of one or more sensors will result in 
activation of the alarm indicator. The control means is responsive to an 
autosecure control signal to place the master control device in the secure 
mode if none of the sensors are activated or, if one or more sensors are 
activated at the time of receipt of the autosecure control signal, to 
place the master control device in the secure mode when all sensors become 
inactive. The control means also includes means for placing the master 
control device in an autosecure mode upon receipt of the autosecure 
control signal and, when in the autosecure mode, for selecting the secure 
mode a predetermined time period after the master control device is placed 
in the access mode if none of the sensors are activated and for placing 
the master control device in the secure mode when all of the sensors 
become inactivated if at least one sensor was activated at the expiration 
of the predetermined time period. 
As embodied herein, the aforementioned control means and placing means 
comprises the control logic 78, RAM memory buffers 84, 86, and 88, and 
instructions stored in program memory 87, as will be described in detail. 
The control means also includes means responsive to an arm control signal 
from the central station for selectively placing each zone independently 
of every other zone into either an arm mode permitting generation of an 
alarm signal or a disarm mode preventing generation of an alarm signal. As 
embodied herein, such responsive means comprises control logic 78, RAM 
memory buffers 84, 86, and 88, and program instructions of memory 87 as 
shown in FIGS. 7B and 7C. 
A specific zone may be placed in autosecure mode by the central station 12 
by sending an autosecure signal to the remote station 14. This places the 
zone in the secure mode if no sensors 53 of the door loop 52 are active; 
that is, if all doors of the zone are closed or if the zone is not armed. 
If this is not the case, the zone will remain in the access mode until 
such time as all sensors 53 of the door loop 52 are restored or the zone 
is disarmed. At this time, the zone will be placed in the secure mode. If 
an authorized user desires entry at this time and activates the keyswitch 
72 to return the zone to the access mode, such entry can be accomplished 
without the generation of an alarm. However, since the zone is in the 
autosecure mode, the zone, instead of remaining in the access mode until 
the keyswitch 72 is once again activated, is returned automatically to the 
secure mode after expiration of a 30 second delay period. In this manner, 
greater convenience is provided to the user with no loss in security to 
the zone. Furthermore, it is possible through the autosecure feature of 
the present invention to permit the central station 12 to place the zone 
in condition to generate an alarm without any action required from the 
users at the remote station. 
The status of each zone is displayed on the panel for each RIM of the 
master control device 16. Thus, the status of arm, reset, autosecure, and 
alarm for each zone is displayed by the LED indicators 30, 32, 34 and 36. 
In addition, capability is provided to generate a local arm signal or a 
siren disable condition when desired. The local arm feature is used when 
the remote station 14 is no longer effectively communicating with the 
central station 12. Siren disable is generally used for maintenance 
purposes. The local arm, siren disable and master reset features are 
global to all four RIMs of the master control device. 
In accordance with the invention, the above-mentioned control means 
includes means for discontinuing a produced alarm signal whenever the 
control means is in the master reset mode and the alarm loop is sensed to 
be a closed circuit. As embodied herein, the discontinuing means comprises 
control logic 78, RAM memory buffers 84, 86, and 88, and program 
instructions contained in program memory 87; and specifically, program 
instructions containing the logic expressed in FIG. 7C to be described 
below. 
The master reset feature provides simpler and cheaper testing of the 
system, both at installation and during periodic maintenance, and is 
initiated by placing the master control device into the master reset mode 
by activating the master reset push-button 46. This condition is sensed by 
the master control device 16 and transmitted to the central station 12. 
The master reset indicator LED 48 is also energized. Next, the zones of 
the RIM which are desired to be tested are armed through either an arm 
command from the central station 12 or a local arm command generated by 
activating the local arm push-button 38. The zone is also placed in the 
secure mode either through operation of the keyswitch 72 or generation of 
an autosecure command from the central station 12. At this time, 
activation of any sensor 53 in the door loop 52 of the specified zone will 
result in an alarm. However, the alarm will be immediately reset when the 
specified sensor 53 is restored. In this manner, a single person can 
physically test each sensor 53 by opening the door associated therewith. 
If the entire system including the sensor 53 is operating properly, the 
siren will sound. The maintenance person will then close the door, causing 
a reset of the alarm condition which, in turn, causes the siren to become 
silent. Each sensor 53 of the door loop 52 of the specified zone can thus 
be easily tested without the necessity for performing a normal reset. 
In accordance with the present invention, means are provided for 
selectively coupling the remotely operated access control system with any 
of the zones such that opening of an associated door causes the control 
means to activate the alarm indicator associated with the coupled zone. As 
embodied herein, the coupling means comprises control logic 78, RAM memory 
buffer 86, program instructions of memory 87, means fixedly associated 
with the remotely operated access control system for storing a value 
uniquely identifying one of the zones, and means for generating an 
electrical signal to the control means corresponding to the stored value. 
Specifically, the storing and generating means comprises DIP switches 55. 
Further in accordance with the invention, the control means comprises means 
for storing in storage locations of RAM memory buffer 86 a quantity 
representative of the specific zone to which the remotely operated access 
control systems associated with these storage locations is coupled. As 
embodied herein, such storing means comprises control logic 78, and 
program instructions of memory 87 as described in FIG. 6A which, upon a 
cold restart, store values from switches 55 in those locations of buffer 
86 designated to hold variables QD1, QD2, 2D1, 2D2, and ZD3. 
As described previously, each remotely operated access control system 22 
has associated therewith a five-position DIP switch 55, each position of 
which establishes a separate one of the logical variables QD1, QD2, ZD1, 
ZD2, and ZD3. Switch 55 thus specifies to which protective zone the 
remotely operated access control system 22 will be coupled. If it is 
desired to change the zone to which such a system 22 is coupled, the 
switch contacts for variables QD1, QD2, are set to specify which of the 
four zone modules contains the desired zone and the switch contacts for 
variables ZD1, ZD2, and ZD3 are set to specify which of the eight zones on 
the selected module is desired. An open switch contact corresponds to an 
active value of the associated logical variable and a closed contact 
corresponds to a restored value. The values of QD1, QD2, ZD1, ZD2, and ZD3 
are read into RAM upon execution of a cold restart. 
Description of the Control Logic 
In order to carry out the functions described above, each master control 
device 16 includes a plurality of instructions stored in program memory 
87. The logic embodied in the instructions contained in program memory 87 
will now be described with reference to the logic flow diagrams in FIGS. 6 
through 10. In these figures, an electrically locked door is sometimes 
referred to as an "auto-door". 
FIGS. 6A-6D is a logic flow diagram of the main loop program. This program 
is continuously executed so long as power is supplied to the master 
control device 16. After starting the program, a determination is made at 
block 102 if this is a "warm restart." If so, a warm restart is performed 
at block 104 wherein the RAM memory 88 is checked for consistency and no 
values are changed. A message is sent at block 105 to the host computer 13 
indicating the warm restart. If a "cold restart" is called for, the cold 
restart initialization is performed at block 106 to set all zones to 
access, to restore all ARMz, RESETz, and AUTOSECUREz logical variables, 
and to load values of ZD1, ZD2, ZD3, QD1, and QD2 from associated DIP 
switches 55. A cold restart message is then sent to the host computer 13, 
as indicated in block 110. 
A determination is made at block 112 if the host input buffer 82 is 
changed. The host input buffer contains the latest value of logical 
variables as stored therein by the master control device 16 due to 
conditions at the remote station 14. The status of these logical variables 
as they were last transmitted to the host computer 13 stored in the 
counterpart buffer 82a. Thus, a comparison of the buffers 82 and 82a 
determines if a change has occurred to the buffer 82a since the last time 
the status of the associated logical variables was transmitted to the 
host. If a change has occurred, then the new values are transmitted at 
block 114 to the host computer 13 and the updated values written into the 
counterpart buffer 8a. 
At block 116, a determination is made as to whether the logical variable 
DOOR CTL of the host output buffer 84 has changed since the last time the 
main loop program for this RIM executed. This is determined by comparing 
the status of DOOR CTL in buffer 8a with its value in the counterpart 
buffer 84A. If a change has occurred, a determination is made at block 118 
as to whether the change was from restored to active. If so, this is an 
indication that the host computer 13 has commanded the electrically locked 
door associated with this RIM to be opened. If so, the Door Open routine 
is called at block 120. If the change of DOOR CTL was from active to 
restored, the Door Close routine is called at block 122. 
A determination is made at block 124 as to whether a system hardware 
failure has occurred. If so, a trouble report is sent to the host computer 
13 at block 126. 
The main loop program continues in FIG. 6B where a determination is made at 
block 126 as to whether a module is present. In a preferred embodiment, 
the circuitry of the control device 16 is organized such that four RIMs 
are present to enable control of up to four remotely operated access 
control systems 22. Protection zone circuitry is contained on up to four 
zone board modules which each contain circuitry for eight protection 
zones. Other types of modules which can be provided in the control device 
16 include auxiliary reader boards, input/output boards, supervisory 
boards, and an analog input board. 
At block 128 a determination is made as to whether a zone board is present. 
If not, a series of checks for the presence of various other types of 
modules is made. If a zone board is present, the Zone Board routine is 
called at block 130. After execution of the Zone Board routine (described 
in greater detail in FIG. 7) a determination is made at block 132 as to 
whether any of the push-buttons 38, 42, or 46 have been pressed. If so, it 
is determined at block 134 if the MASTER RESET logical variable stored in 
host buffer 82 has changed state. If so, the master reset indicator LED 48 
is changed to the appropriate state at block 136. This change is reported 
to the host at block 138. In a similar manner, it is determined at blocks 
140 and 146 if the SIREN DISABLE logical variable or LOCAL ARM logical 
variables, respectively, in the buffer 82 have changed state. If so, 
appropriate indicator LEDs 44 and 40 are placed in the proper state at 
blocks 142 and 148, respectively, and these actions reported to the host 
computer at block 144 and 148, respectively 13. 
If a zone board is not present as determined at block 128, similar checks 
and subroutine calls are made at blocks 128a-128d and 130a-130d for 
auxiliary reader boards, I/O boards, supervisory boards, and analog 
boards. 
At block 152, it is determined if the variables associated with a remotely 
operated access control system 22 have changed state. This is determined 
by comparing the appropriate variables in the external input buffer 86 
with the status of these variables during the previous execution of the 
main loop program by reference to counterpart buffer 86a. If so, a 
determination is made at block 154 if the LOCK SENSE variable has changed 
state. If so, it is checked whether the change was from restored to active 
at block 156. If yes, a 30-second door prop timer is set running at block 
158. This timer is provided such that normal opening and closing of the 
door will not be interpreted as an abnormal condition and will not be 
reported to the host computer 13, thus reducing congestion of the 
communication lines 26 and 28. If the change was from active to restore, 
the door prop timer is turned off at block 160 (FIG. 6C). 
Continuing to FIG. 6C, it is determined at block 162 if the DOOR PROP 
variable in the host input buffer 82 is set. If so, this variable is reset 
at block 164 and the change reported to the host computer 13 at block 166. 
If the LOCK SENSE variable was not changed at block 154, a determination is 
made at block 168 if the DOOR POS variable (referred to in the Figures as 
KLR door) in buffer 86 has changed, that is, has the position of the 
electrically locked door changed. If so, and if the change was from 
restored to active as determined at block 170, it is determined at block 
178 whether the door timer is running. If the timer is running, this is an 
indication that the electrically locked door associated with this RIM was 
properly opened in response to an entry or exit request. If not, this is 
an indication of unauthorized opening of the electrically locked door. A 
command is generated at block 180 to open the bolt of the electrically 
locked door to limit damage which could occur due to a break-in. That is, 
the variable DOOR CTL in buffer 84 is activated. An actual alarm signal is 
not generated at this time, since all alarm signals are produced in the 
Zone Board routine of FIGS. 7A-7D. However, at block 182 a door open flag 
on the zone associated with the electrically operated locked door for this 
RIM is set to indicate an illegal entry. 
If the change in the DOOR POS variable was from active to restored, the 
door open flag of the appropriate zone is reset at block 184. 
If the DOOR POS variable has not changed, it is determined if the ENTRY 
variable changed at block 186. If so, and if the change was from restored 
to active as determined at block 188, then the alarm bit on the zone 
associated with the electrically locked door for this RIM is reset at 
block 190 and the door open routine called at block 192. 
If the ENTRY value has not changed, it is determined at block 194 if the 
EXIT value has changed. If so, and if the change was from restore to 
active as determined at block 196, the door open routine is called at 
block 198. Note that an EXIT will not result in a reset of an alarm at the 
associated zone. 
If no push-button has changed state on this RIM, it is determined at block 
200 if all four positions in which a zone module board could be inserted 
have been checked. If not, the program executes the steps at blocks 126 
through 198 for each of the remaining module positions. If all the module 
positions have been checked, the Main Loop program returns to block 112 
for the next execution cycle. 
The Door Open and Door Close routines are shown in FIG. 6D. In the Door 
Open routine, a door open timer is set running at block 202. Next at block 
204, a blinking LED on the card reader through which the entry request was 
generated is turned off. At block 206, the card reader LED is steadily 
energized. This indicates to a person requesting entry that the 
identification number on his card has been approved and the electrically 
operated lock is being unlocked. The logical variable DOOR PWR of the 
buffer 88 is then activated which removes power from the relay 56 of the 
electrically operated door to allow the door bolt 62 to return to the 
unlocked condition. At this point, the door can be opened by the person 
desiring entry. 
In the Door Close routine, the logical variable LOCK SENSE is checked at 
block 210 to determine if the power is still being withheld and that the 
bolt 62 is still in the unlocked condition. If so, the Door Close routine 
is exited. If LOCK SENSE is active, it is determined at block 212 whether 
the host computer 13 has this door permanently opened. If this is the 
case, the Door Close routine is exited. If not, the LED on the associated 
card reader is turned off at block 214, and the DOOR PWR logical variable 
is restored at block 216 to cause power to be applied to the relay 56 and 
switch the bolt 62 to the locked position. 
The logic flow diagram of the Zone Board routine is shown beginning on FIG. 
7A. At block 218, it is determined whether there has been a change in the 
external input buffer 86 indicating that one of the input devices 18 has 
changed state since the last time the Zone Board routine was executed. If 
so, it is determined at block 220 whether the logical variable KEYSWITCH 
has changed, indicating that the access or secure status of the zone has 
changed. If so, and if the change was from restored to active as 
determined at block 222, this indicates that the zone has been changed 
from the access mode to the secure mode. If so, it is determined at block 
224 if the zone is in the autosecure condition, by checking the AUTOSECURE 
logical variable for the associated zone in host output buffer 84. If not, 
the access-secure mode of this zone is toggled at block 226, the ACCESS 
variable of host input buffer 82 is toggled, the SECURE variable of the 
external output buffer 88 is toggled at block 228 to change the status of 
the secure light 74 at the zone, and the change in status of the 
access-secure mode is sent to the host computer at block 230. 
If AUTOSECURE is active, a determination is made at block 232 if the access 
mode is active, as determined by the ACCESS variable of host input buffer 
82. If so, the access timer is restarted at block 234 to provide a full 
time delay period from the time the user has last activated the keyswitch 
72 until the status of the zone is automatically switched to the secure 
mode. If the access mode is not active, then the ACCESS variable is set 
active in host input buffer 82 at block 236 and the SECURE lamp 74 turned 
off at block 238. The change is then sent to the host computer 13 at block 
240 and the access timer turned on at block 242. 
Next, it is determined at block 244 whether the CTI contact, associated 
with an auxiliary contact of, for example, a janitor's door, has changed. 
If so, and if the change was from restored to active as determined by 
block 246, then the CONTACT variable for this zone in host input buffer 82 
is set and the result transmitted to the host computer 13 at block 250. If 
the change in the CTI variable was from active to restored, then the 
CONTACT variable for this zone is restored in the host input buffer 82 at 
block 252 and the result transmitted to the host computer 13 at block 254. 
It is determined at block 256 whether the tamper loop 50 of this zone has 
changed; that is, if the logical variable TAMPER LOOP for this zone in 
input buffer 86 has changed. If so, and if the change is from restored to 
active as determined by block 258, the TAMPER variable is set in host 
input buffer 82 at block 260 and the result transmitted to the host at 
block 262. If the change in the variable TAMPER LOOP is from active to 
restored, it is determined at blocks 264 and 266 whether the RESET 
variable of host output buffer 84 or the MASTER RESET variable of host 
input buffer 82 are active. If either of these variables is active, this 
indicates that a reset has indeed been called for, and the TAMPER variable 
for this zone is stored in host input buffer 82 at block 268. The result 
is transmitted to the host at block 270 and the siren tamper flag reset at 
block 272. The siren tamper flag will be utilized by the routine in block 
352 of FIG. 7C. Next, it is determined at block 274 whether the door loop 
52 for this zone has changed, that is, if the DOOR LOOP variable of 
external input buffer 84 has changed from the previous execution of this 
routine. If so, and if the change is active as determined by block 276, 
the door loop bit is set on in block 278. 
If the change in DOOR LOOP variable is not active, the door loop bit is 
reset at block 279. At block 280, it is then determined whether the ACCESS 
variable for the zone in the host input buffer 82 is active. If so, two 
seconds are added to the access timer at block 282. The access timer is 
used to keep track of the 30-second autosecure time period. In block 282, 
the time period is extended by 2 seconds when the door loop closes in 
order to delay (by 2 seconds) the switching of the zone back to secure 
mode. 
Referring to FIG. 7B, the zone board routine continues at block 284 where 
it is determined whether there has been a change in host output buffer 84 
since the last time the zone board routine executed. If so, it is 
determined at block 286 if the ARM variable for this zone has changed, and 
if the change is active as determined at block 288, the ARM variable for 
the zone in the external output buffer 88 is activated to turn on the ARM 
LED 30 for the zone and to turn off a 12 volt utility contact. 
At block 292 it is determined if this RIM is in the local arm condition as 
determined by the LOCAL ARM variable of host input buffer 82. If not, the 
ARM variable for this zone in external output buffer 88 is restored and 
the arm LED 30 for this zone is extinguished at block 294. 
It is determined at block 296 whether the RESET variable in the external 
output buffer 88 has changed and, if the change is from restored to active 
as determined by block 298, the reset LED 32 for this zone is energized at 
block 298A. If the change, as determined by block 298, is from active to 
restore, it is determined at block 298B whether the MASTER RESET variable 
of external output buffer 88 is active. If not, the master reset LED 48 is 
extinguished. Finally, at block 299 it is determined whether the 
AUTOSECURE variable in external output buffer 88 for this zone has 
changed. If so, the autosecure LED 34 for this zone is toggled at block 
299A. 
At block 300, it is determined whether the ACCESS variable for this zone in 
host input buffer 82 is active. The access timer is checked at block 302 
and if it has expired, a determination is made at block 304 if the 
AUTOSECURE variable for this zone in host output buffer 84 is active. If 
so, it is determined if the DOOR LOOP and DOOR POS in external input 
buffer 86 are both active, indicating that all doors and the electrically 
locked door for the zone are all in a closed position. If so, the ACCESS 
variable in host input buffer 82 and the ACCESS LED variable in external 
output buffer 88 are restored at block 308. The host input buffer 82 is 
then transmitted to the host at block 310. At this point, the zone has 
automatically been placed in the secure mode without any interaction by 
the user, following expiration of the predetermined time period after the 
zone was placed into the access mode. 
If any of the doors of the zone including the electrically locked door are 
open as determined at block 306 following expiration of the access time 
period, a determination is made at block 312 and block 314 if either the 
LOCAL ARM variable for this RIM in host input buffer 82 or the ARM 
variable for the zone in host output buffer 84 are restored. If both of 
these variables are restored, then the zone is automatically placed in the 
secure mode at blocks 308 and 310. The operations of blocks 308 and 310 
are not performed if either the LOCAL ARM or ARM variables are active. 
Referring now to FIG. 7C, it is determined at block 316 whether the ALARM 
variable for this zone in host input buffer 82 is active. If so, and if 
the LOCAL ARM variable for this RIM in host input buffer 82 is active as 
determined at block 318, a determination is made at block 320 if the DOOR 
LOOP variable for this zone is restored and the door flag is off; that is, 
if all doors in this zone, including the electrically locked door, if 
present, are closed. If this is the case, a determination is made at block 
322 if the MASTER RESET variable in host input buffer 82 is active. If so, 
at block 324 the ALARM variable for this zone is restored, the alarm LED 
36 for this zone is turned off and the siren flag is turned off. If the 
MASTER RESET variable is not active, it is determined at block 323 if zone 
reset is active. If so, the functions of block 324 are executed. 
If any of the doors of this zone including the electrically locked door are 
open, as determined at block 326 (referenced in FIG. 6C at block 182) by 
checking the DOOR LOOP variable for this zone and the door open flag, it 
is determined if either the LOCAL ARM variable for this RIM or ARM 
variable for this zone are active at blocks 328 and 330, respectively. If 
so, it is determined at block 332 if the ACCESS variable for this zone in 
this host input buffer 82 is active. If not, this means that the zone is 
both armed and secured and an unauthorized opening of the door has taken 
place. Accordingly, at block 334, the ALARM variable in host input buffer 
82 is activated and the ALARM LED 36 for this zone is turned on. These 
actions are reported to the host at block 336 and the program advanced to 
block 350. 
If all doors for the zone are closed, a determination is made at block 338 
of whether the siren for this zone is on; that is, if the SIREN variable 
of external output buffer is active. If so, determinations are made at 
blocks 340, 342, and 344 whether either the siren time is up, the SIREN 
DISABLE variable for this zone is active, or both ALARM and TAMPER 
variables for this zone in host input buffer 82 are off. If any of these 
conditions of blocks 340, 342 and 344 are present, the SIREN variable of 
external output buffer 88 is turned off at block 346. Otherwise, the 
program advances to block 358 of FIG. 7C. If the SIREN variable is not 
active as determined by block 338, it is determined in block 346 whether 
the ALARM variable of host input buffer 82 for this zone is active. If so, 
and if the alarm bit (blocks 324, 334) is off, as determined in block 348, 
then a determination is made at block 350 if the SIREN DISABLE variable 
for this RIM in host input buffer 82 is active. If not, and if both the 
alarm and tamper siren flags are off, then the siren 5-minute timer is 
turned on at block 356 and the SIREN variable of external output buffer 88 
is activated. 
Next, at block 358 of FIG. 7C the SIREN variables for all zones are applied 
to the actual siren output terminals to sound the sirens for those zones 
in which the siren variable is active. A watchdog timer is then toggled at 
block 360 to indicate that the zone board routine has successfully 
executed. If a problem should develop in the zone board routine and this 
timer does not get toggled at the expiration of a predetermined time, a 
signal would be generated and transmitted to the host computer 13 
indicating trouble on the zone board. At block 362, all of the variables 
of the external output buffer 88 are applied to the actual output 
terminals to appropriately control the output devices 18 connected 
thereto. At block 364, a determination is made as to whether the zone 
board routine has been executed for all eight zones associated with this 
RIM. If not, the routine is executed for the remaining zones of the RIM. 
If so, the routine is exited. 
The Main Loop routine, including the zone board routine, executes 
continuously in the master control device 16 unless interrupted by a 
higher priority routine. Routines which execute on an interrupt basis 
include the Timer Interrupt routine, the Communication Interrupt routine, 
and the Card Reader Interrupt routine. 
The logic flow of the timer interrupt routine is shown in FIGS. 8A-8C. This 
routine executes every 1/8 second as determined by the timer 85 of FIG. 4. 
The Timer Interrupt routine begins at block 600 at which all registers of 
the control logic 78 are saved. Next, at block 602 a determination is made 
whether a card read is pending. If so, an LED on the associated card 
reader is toggled at block 604. Since the timer interrupt routine executes 
every 1/8 of a second, the LED on the card reader will blink at a rate of 
four times per second while a card read operation is pending. The blinking 
operation is executed for all card readers serviced by this RIM, master 
control device 16 up to a total of 12 readers (standard complement of four 
readers plus an expansion reader board of up to eight readers). The 
blinking LED for the card readers is the only function which must be 
performed every 1/8 of a second. All other interrupt operations are 
performed at intervals of one second or longer. Accordingly, at block 608 
a determination is made whether a one-second time period has expired. If 
not, the timer routine reloads the 1/8 second timer at block 610 and exits 
to permit the Main Loop routine to resume execution. 
At block 612, the one-second counter is reloaded and a determination made 
at block 614 whether the door open timer is active, that is, if the DOOR 
PWR variable of the external output buffer 88 is active. If so, it is 
determined at block 616 if the predetermined time period for the door open 
timer has expired and, if so, a determination made if the electrically 
locked door is still being held open. That is, at block 618 a 
determination is made if the DOOR POS variable is active. If not, the Door 
Close routine is called block 620. If the door is open, two seconds are 
added to the door open time period at block 622. 
At block 624, it is determined whether the RIM communication timer is 
running. Whenever a message is sent from the master control device 16 to 
the host computer 13, an acknowledgement is received back from the host 
upon successful receipt of the message. Whenever a message is sent, the 
RIM communication timer is set. The timer is reset upon receipt of an 
acknowledgement. 
At block 626, it is determined whether the time period of the RIM 
communication timer has expired and if so, the message is retransmitted. 
The master control device 16 keeps track of the number of such 
retransmission for each message, up to a predetermined maximum number of 
retransmissions as determined from the host computer. At block 628, it is 
determined whether this is the final such retransmission. If so, at block 
628A the "going-off line message" is loaded into the communication buffer, 
the off-line flag is set and the on-line LED located inside the master 
control device 16 is turned off. 
If this is not the final retransmission, the previously sent message is 
loaded into the communication buffer at block 628B. At block 628C, the 
contents of the communication buffer are sent to the host computer 13. A 
determination is made at block 629 (FIG. 8B) if a Card Read was pending. 
If so, the RIM card read routine shown in FIG. 10 is called. 
At block 630 on FIG. 8B, it is determined if the RIM 3-minute communication 
timer has expired. In order to maintain maximum reliability for the entire 
system, the host computer 13 generates a message to each RIM at least 
every minute, even if no data is to be passed. Thus, at block 630 a 
determination is made if the three-minute communication timer is running. 
At block 632, it is determined whether this timer period has expired and 
if so, at block 634 the three-minute timer is turned off, the acknowledged 
communication timer is set, the retry count is loaded and the off-line 
message is loaded in the communication buffer. This is so that the RIM 
will be properly set into offline mode whenever communication with the 
host is lost for 3 minutes. This message is sent at block 636. 
At block 638, it is determined whether the lock sense timer is running. 
This timer is started whenever the electrically locked door bolt is 
activated. A determination is made at block 640 whether the door has been 
opened 30 seconds. If so, this is an indication that the door has been 
propped open, a condition which the host should be aware of since it 
represents a possible loss of access control. Thus, at block 642 the PROP 
variable is activated in the host input buffer 82. The contents of the 
host input buffer 82 are then sent to the host at block 646. 
Since each master control device has a potential to operate up to 12 
authorized entry devices, and thus has a potential capacity of up to 12 
RIMs, a determination is made at block 648 of whether all RIMs on this 
master control device have been serviced. If not, the timer interrupt 
routine returns to block 614 to sequentially service the remaining RIMs. 
At block 650, it is determined whether a two-second time period has elapsed 
since last execution of the remainder of the timer interrupt routine. If 
not, the 1/8 second timer is restarted at block 650 and the timer 
interrupt routine exited. If two seconds have expired, the two-second 
counter is reloaded at block 654 and a determination is made at block 656 
if the perimeter prop timer is running. This timer is operated whenever 
the perimeter loop 51 has been activated, and if the timer has expired as 
determined by block 658, the PERIMETER PROP variable is set in the host 
input buffer at block 660, and this buffer transmitted to the host at 
block 662. Again, normal entry and exit through the perimeter doors 
monitored by the perimeter loop 51 is not transmitted to the host 
computer. However, if the door remains opened for more than a 
predetermined period of time, this is an indication of a possible abnormal 
condition and the host computer is so informed. 
At block 664, it is determined whether the access timer is running. This 
timer is set whenever a zone is operated from secure mode to the access 
mode, while the zone is in the autosecure condition. If the timer is 
running and if the time period thereof has expired as determined by block 
666, the timer is turned off at block 668 and a flag set for use by the 
Zone Board routine to cause the Zone Board routine to automatically return 
the zone to the secure mode. 
At block 670, a determination is made as to whether a siren timer is 
running and if its five-minute time period has expired, as determined by 
block 672. If so, the siren timer is turned off at block 674 and a flag 
set for use by the Zone Board routine which will silence the siren on the 
next execution of the zone board routine. 
A determination is made at block 676 as to whether all zones have been 
properly serviced by the timer interrupt routine. If not, the routine 
returns to block 664 to service the remaining zones. 
At block 678 of FIG. 8C, a determination is made of whether the 
three-minute "all communications" timer has expired; that is, if no 
communications whatsoever have been received by this master control device 
16 for three minutes. This would be an indication that the communication 
interface 83 has possibly failed. Accordingly, at block 680 the timer is 
reset to zero and a flag set for use by a trouble routine to restart the 
communication interface 83. 
At block 682 of FIG. 8C, the 1/8 second timer is reloaded and restarted to 
complete execution of the timer interrupt routine. All registers of the 
control logic 78 are restored at block 684 to their condition prior to the 
occurrence of the timer interrupt and the Timer Interrupt routine is 
exited. 
The Communication Interrupt routine is shown in FIGS. 9A through 9C. This 
routine is entered whenever an interrupt is generated by either the 
control logic 78 as a result of a desire to transmit a message or by the 
communication interface 83 as a result of the receipt of an incoming 
message from either the host or another master control device 16. As can 
be seen in FIG. 1, a plurality of master control device 16 may be 
connected in a loop configuration at each remote station 14. 
Each message transmitted over the communication lines 24, 26, and 28 
consists of a plurality of 7-bit bytes. The first byte in each message is 
a RIM address having a value of 0-77 (octal). Next, is a function code 
having a value of 100-177 which specifies the type of message. Following 
the function code may be any number of data bytes each having a value of 
100 plus the data value. Finally, an end-of-message byte having a value of 
15 is transmitted to terminate the message. 
In normal operation, requests for entry through an electrically locked door 
are passed through the host computer 13. That is, a determination is made 
as to whether the holder of a specific number which is unique to the 
identification card placed in the card reader will be allowed to enter 
through the electrically locked door. The number encoded on the 
identification card is split into two portions, an off-line code and an 
individual ID number. During normal operation, both the off-line code and 
the individual ID number are scrutinized by the host computer in 
determining whether entry should be permitted. However, under certain 
conditions it is possible that communication channels between the 
individual RIMs of the remote station 14 and the host computer can become 
overloaded. Because a RIM may not receive an acknowledgement from the host 
of one of its messages, the RIM may go into the off-line mode. When a RIM 
is off-line, requests for entry through card readers will be serviced 
locally at each RIM. However, only the off-line code is checked, not the 
individual ID number. In standard practice, all users associated with an 
electrically locked door will have the same off-line code but a unique 
individual ID number. The host computer will communicate the off-line code 
for each RIM to the specified RIM. Thus, when a RIM is off-line all users 
having the same off-line code will be permitted entry by the RIM. Messages 
for each RIM are transmitted from the host computer to the first master 
control device 16 at the remote station 14. If the message is addressed to 
a RIM associated with this master control device it will be processed 
accordingly. If, however, it is addressed to a RIM at a downstream master 
control device 16, the message is repeated, or echoed, by the first master 
control device on a byte-for-byte basis to the downstream master control 
device. 
The Communication Interrupt routine stored in program memory 86 of the 
master control device 16 will now be described. At block 400, all 
registers of the control logic 78 are saved and a determination made at 
block 402 as to whether the interrupt which called the communication 
interrupt routine was produced by a message word arriving from the host 
computer. If not, a determination is made at block 404 of whether the 
interrupt generated by a message to be transmitted from this RIM to the 
host. If not, the communication routine is exited. Otherwise, it is 
determined at block 406 whether if the message is partly transmitted, that 
is, the word waiting to be sent to the host is other than the first word 
of a message. If so, and if this is a message that was actually generated 
by this RIM (as opposed to a message generated by another RIM which is 
being echoed to a downstream master control device) the address of the 
next byte to be transmitted is determined at block 408 and sent at block 
410 over the appropriate transmission line 26 or 28. The address of the 
next byte to be transmitted is then determined and saved at block 412 and 
a determination made at block 414 of whether this represents the 
conclusion of the message. If not, the routine is exited. Otherwise, a 
determination is made at block 416 of whether there is an echoed message 
waiting to be transmitted. If so, an echo flag is set at block 414 and the 
routine is exited. Otherwise, the transmitter flag is restored and the 
transmitter of the communication interface 83 turned off at block 418. The 
routine is then exited. 
If it is determined at block 406 that the message is not partly 
transmitted, that is, the byte waiting to be transmitted represents the 
first byte of a message, the transmitter-in-use flag is set at block 420 
and a determination made at block 422 whether a message generated by this 
RIM is waiting to be transmitted. If so, the address of the RIM message is 
determined at block 424 and the byte is transmitted in blocks 410 through 
419 in the manner described previously. If there is not a message from 
this RIM waiting to be transmitted, a determination is made at block 426 
if all RIMs for this master control device have been serviced. If not, the 
remaining RIMs are serviced beginning at block 422. 
If it is determined that no RIMs in this master control device have a 
message waiting to be transmitted, a determination is made at block 428 as 
to whether there is an echoed message waiting to be transmitted, that is, 
a message generated by an upstream master control device 16 which was 
received and stored by this master control device until such time as all 
messages generated by its RIMs could be transmitted. If not, the routine 
advances to block 419 in the manner previously described. If there is an 
echoed message waiting to be transmitted, the address of this message is 
loaded at block 430 and the first byte transmitted at block 432. The 
address of the next byte to be transmitted is then calculated at block 434 
and a determination made at block 436 of whether the echoed message 
transmission has been completed. If not, the routine is exited. Otherwise, 
the transmitter flag is restored and the transmitter turned off at block 
419. 
If it was determined at block 402 that the communication interrupt was 
generated by the arrival of a message from the host, a determination is 
made at block 440 of whether the byte waiting is part of a message, the 
beginning of which has been previously received. If not, then the byte 
waiting represents the first byte of an incoming message and a 
determination is made at block 442 (FIG. 9B) as to whether the byte has 
been received with a parity error. If not, a determination is made at 
block 444 of whether the received byte is a 14 or 15 (octal). These two 
RIM addresses are not assigned to any RIMs in any remote station 14, but 
are used by the host computer to generate a message which will be echoed 
by each master control device 16 at the remote station 14 and return to 
the host computer. In this manner, the host computer can determine whether 
the integrity of the communication loop through the remote station 14 is 
maintained. If the received byte is a 14 or 15, then it is determined at 
block 446 whether the transmitter is now in use, and if not, the 
transmitter in use flag and echo flag are set at block 448. The received 
byte is then transmitted to the host at block 450 and a determination is 
made 452 of whether the message has been completed. If not, the routine is 
immediately exited. Otherwise, the transmit and echo flags are reset at 
block 454 prior to exiting the routine. 
If it is determined at block 446 that the transmitter is now in use, that 
is, the transmitter is in the process of sending a message generated by 
this RIM, then the incoming byte is saved at block 456 and the address of 
the next available storage location in memory for storage of subsequent 
byte is determined. Next, it is determined whether block 458 is the last 
byte, that is, if this is the end of message character 15 (octal). If not, 
the routine is immediately exited. Otherwise, the echo message ready flag 
is set at block 460 prior to exiting a routine. 
If it is determined at block 447 that the incoming byte is not a 14 or 15, 
then it is determined at block 462 whether the value of the RIM address in 
this first character of the received address is greater than or less than 
the RIM numbers associated with this master control device 16. If so, the 
message is not destined for this master control device and is an echo 
message to be processed to blocks 446 through 460. If the incoming 
character is equal to the RIM address associated with this master control 
device as determined by block 462, the acknowledge communication timer and 
three-minute communication timers are reset at block 464. Again, time out 
of either of these timers is an indication of a communication failure. 
Thus, if an incoming message has been received for a RIM associated with 
this master control device, then the communication facilities are 
functioning normally and the failure timer should be reset. 
If the parity of the received byte is bad, then the parity flag is reset at 
block 443 to ignore this incoming byte and the routine exited. If it is 
determined at block 440 that the incoming byte represents the next byte in 
an echoed message the beginning of which is already received, a 
determination is made at block 466 of whether a parity error has occurred 
on this byte. If so, the parity flag is set at block 443 and the routine 
exited. Otherwise, a determination is made at block 468 if this message is 
addressed to a RIM on this QUAD. If so, the byte is processed at block 
464. Otherwise, a determination is made of whether this message is being 
stored since the transmitter busy flag is set. If not, the byte is 
transmitted as described in block 450 through block 454. Otherwise, the 
byte is processed as described in blocks 456 through 460. 
If this byte is part of a message addressed to this RIM as determined at 
block 440, and if the parity on this block is bad, a retry message will be 
generated in a manner to be described below. Otherwise, the byte is saved 
in a buffer memory and the address of the next available memory storage 
location computed at block 474. If the message is not complete, as 
determined at block 476 then the routine is immediately exited. Otherwise, 
the watchdog communication and three-minute communication timers are reset 
at blocks 478 and 480, respectively. The off-line flag is reset at block 
482 and determination made at block 484 of whether this is a command to 
set the off-line code for this RIM. As discussed above, this is a code 
which is used when card reader entry requests are to be processed locally 
by this RIM, rather than by the host computer. 
If this is a command to set the off-line code for this RIM, the new 
off-line code is stored at block 486 in a buffer associated with this RIM 
and the routine exited. Otherwise, a determination is made of whether this 
message is a command to set a new off-line mask, a quantity also used when 
the RIM is in the off-line mode. If so, the new mask is stored at block 
490 in the correct buffer for this RIM and the routine exited. Otherwise, 
a determination is made at block 492 (FIG. 9C) as to whether the incoming 
message represents a specification by the host computer of the number of 
times a message to the host will be transmitted before determining that a 
communication failure has occurred. If so, the new retry count is placed 
in the correct buffer at block 494 and the routine exited. Otherwise, it 
is determined at block 496 if this message represents the command to open 
the electrically locked door associated with this RIM. If so, the correct 
door open time is loaded at block 498. The door open time is the interval 
during which the door remains unlocked in response to an entry or an exit 
request. Since this message tells the RIM that an authorized entry is 
occurring, any alarm condition occurring on the zone associated with this 
RIM is reset at block 500. The Door Open routine is called at block 502 
and the communication interrupt routine exited. 
Referring to FIG. 9C if the incoming message represents a specification of 
the number of seconds a door is allowed to remain unlocked, as determined 
at block 504, the new door open time is stored in the correct RIM buffer 
location at block 506 and the routine exited. If this message represents a 
change in a variable in the host output buffer 84, as determined at block 
508, the incoming message data is written into host input buffer 82 at 
block 510 and the routine exited. 
A determination is made at block 512 as to whether the incoming message 
represents a request from the host to repeat the last message which was 
transmitted from this RIM. If so, the retry count and retry timer are 
loaded and set at block 514, the transmitter turned on at block 516, and 
the routine exited. It is then determined at block 518 whether the 
incoming message represents an input status request. If so, the host 
output buffer 84 for this RIM is loaded at block 520 and the message 
processed at blocks 414 and 416 as previously described. 
Finally, at block 522 it is determined whether the incoming message is an 
acknowledgement of a previous message transmitted by this RIM. If so, it 
is determined at block 524 if a card read was pending. If so, the 
information read from the card is placed in the message buffer and the 
message processed as described previously in blocks 514 and 516. 
Otherwise, it is determined at block 528 whether the acknowledgement is in 
response to a card read; if not, the outine is immediately exited. 
Otherwise, this is an indication that the host has declined to open the 
electrically locked door in response to a card read processed by this RIM. 
The flashing LED and the associated card reader is turned off at block 530 
and the routine exited. If it is determined at block 522 that this is not 
an acknowledgement of a previous message, then the previous message will 
be loaded at block 522 and retransmitted to the host through blocks 514 
and 516. It should be noted that each indication of an exit from the 
communication interrupt routine, block 534 is first executed such that the 
communication interrupt is reset and all registers are restored. 
The logic of the Card Reader Interrupt routine is shown in FIG. 10. 
Whenever an identification card is inserted into a card reader or a number 
sequence keyed into a numeric keypad, the associated authorized entry 
device generates an interrupt to the control logic 78 and supplies the 
value of the identification code obtained from either the identification 
card or the keypad entry sequence, as appropriate. The card reader 
interrupt routine is then executed. At block 550, the routine saves all 
registers of the control logic 78 and locks out all readers except the one 
sending the current value. A determination is made at block 552 as to 
whether the card has been properly read. If not, the routine is 
immediately exited. Otherwise, a determination is made at block 554 as to 
whether this RIM is currently off-line, that is, whether the host has 
indicated that the RIM is to determine locally whether an entry should be 
permitted. If so, a logical AND is performed at block 556 between the 
value received from the card reader and the off-line mask previously 
stored in the RIM by a message from the host computer. A determination is 
then made at block 558 of whether the result of the operation of block 556 
is the same as the off-line code also previously stored by the host 
computer in the RIM. If not, the routine is immediately exited. Otherwise, 
the card read is treated as a valid entry request and the alarm bit on the 
proper zone is reset at block 560. The Open Door routine is called at 
block 562 and the routine exited. 
If a determination at block 554 that the RIM is not off-line, then a 
determination is made at block 555A if a transmitter is currently in use. 
If so, the card read ready flag is set at block 555B so that the 
Communication Interrupt routine will transmit the card read value to the 
host as soon as the transmitter is available. The card reader LED is set 
flashing at block 560C and the routine exited. If the transmitter is 
currently free as determined by block 555A, then the reader LED is set 
flashing at block 563. The card read message is then transmitted to the 
host at block 564. Exit routine operations are then performed at block 566 
by restoring all readers and registers. Execution of the card reader 
interrupt routine is not complete. 
It will be apparent to these skilled in the art that various modifications 
and variations can be made in the access control and security alarm 
apparatus and method of the present invention without departing from the 
scope or spirit of the invention. Thus, it is intended that the present 
invention cover the modifications and variations of this invention 
provided they come within the scope of the appended claims and their 
equivalents.