Operation; Security Mode; How To Enter Security Mode; How To Exit Security Mode - Black Box Programmable Security Guard Manual

4.1 Security Mode

In Security Mode the PSG will monitor received
data and input control leads (if applicable) until
security barriers are successfully negotiated.
4.1.1 H E S
OW TO NTER
You can enter security mode after you do any of the
following:
• Reset the unit.
• Exit from Program Mode.
• Exit from Pass-Thru Mode.
4.1.2 H E S
OW TO XIT ECURITY
• Enter Program Mode.
• Enter Pass-Thru Mode.
4.1.3 H PSG R
OW THE
• Any connected modem links are disconnected,
and the password retry and timer values are
reset.
• The time limit is exceeded when password(s) are
being entered.
• The modem connection is broken (DCD input
becomes inactive for 10 milliseconds when
modem controls are enabled).
• Unsuccessful attempt at a callback (DCD does
not become active after the response string has
been transmitted when modem controls are
enabled).
• Exit command is issued to break modem link.
4.1.4 P V
ASSWORD ALIDATION
You can program the unit for 64 different primary
and secondary passwords, 1-32 characters long. The
passwords may be valid at either port or both, and
passwords may also be valid at only certain times of
the day. Received passwords must be immediately
followed by a carriage-return character. The PSG
will compare the string of received data preceding a
carriage return (maximum of 32 characters) to the
programmed passwords that are valid for that port
at that time of day. Note that you have a certain

4. Operation

M
ECURITY ODE
M
ODE
S M
EENTERS ECURITY ODE
amount of time to enter a valid password. If you
don't enter the password in this time period the
PSG will reenter Security Mode.
If the PSG receives a password in error the unit
can optionally transmit a status message back to the
user ("invalid password"). The unit can be
configured for 1, 2, 3, or infinite retries at entering
a valid password. Once the user meets this limit the
unit will go into a submode called "Security Lock-
Out" mode. In this mode, the unit will ignore all
input from the sending port until the unit reenters
Security Mode. The PSG will reenter Security Mode
when the password timeout expires or when
modem controls are enabled.
If the PSG receives a valid password before the
retry count is met and the password timeout
expires, then the unit will check whether the
individual password it received has a response string
associated with it and whether modem controls are
enabled for that port.
If no response string is present, the unit will not
attempt to call the user back. It will go directly to
SECONDARY PASSWORD VALIDATION. If the
unit doesn't receive a password, refer to Section
4.1.6.
4.1.5 C A
ALLBACK FTER
If it is configured to transmit status messages, the
unit will transmit "PREPARE FOR USER
LOCATION VERIFICATION." Then it will call back
using the response string for that password as a
dialing string. If the dialing string contains
embedded carriage returns, you can enter the
returns as an ASCII period ("."). This callback
feature adds additional security if a computer
hacker stumbles across a password.
The PSG will then disconnect the attached
modem by dropping DTR output for 3 seconds.
The PSG next calls the user back at the appropriate
dialing string. See Section 4.5 ("Modem Control
Procedures") for a more detailed description of this
procedure. If another modem does not answer the
call (DCD input is not active), the PSG will abort
the callback by hanging up the local modem and
reentering Security Mode.
CHAPTER 4: Operation
P V
ASSWORD ALIDATION
15