ADTRAN DSU IV ESP, User Manual

Page: 91 / 194

Chapter 9. Configuring Dial Options
61204011L1-1 DSU IV ESP User Manual 9-11
DBU Options for ISDN Card
Switch Type
This option selects the type of telco CO switch providing the ISDN
service. There are three options for ISDN switch types:
• AT&T 5ESS
• NT DMS-100
• National ISDN
DBU Passcode
The dial backup passcode adds an additional level of security to the
DSU IV ESP. A passcode of one to ten characters can be
programmed into the unit.
When a dial backup connection is established, the originate unit
transmits a pre-programmed passcode to the answer unit over the
dial backup connection before the connection is considered valid.
The answer unit compares the received passcode to a pre-
programmed passcode. If the passcode matches, the receive unit
sends a
P
ASSCODE
OK message to the originate unit and goes on-
line. If the passcode does not match, the receive unit sends an
Invalid Passcode message to the originate unit and terminates the
dial backup connection. If a passcode is not received by an answer
unit with passcode enable, or if the
P
ASSCODE
OK message is not
received by an originate unit with passcode enable, the dial backup
connection is terminated.