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CHAPTER 9: Configuring Dial Options
9.1 Phone Numbers
The CSU/DSU MS DBU stores up to 10 numbers of 36 digits each. Edit a phone
number by reentering the entire number. This process overwrites the previously
stored number.
Table 9-1 shows the AT commands available for the Phone Number options.
ISDN D
IAL
B
ACKUP
Setting the Service Profile Identifier (SPID)
For ISDN dial backup, the service profile identifier (SPID) is stored in Stored
Number 9. The SPID is a sequence of digits identifying ISDN terminal equipment
to the ISDN switch when more than one ISDN set has been attached to the same
central-office line. The SPID is assigned by the telco when the ISDN line is
installed and normally resembles a phone number.
Only the AT&T 5ESS switch is capable of recognizing a point-to-point
configuration, eliminating the need for a SPID. All other switch types
require a SPID.
Setting the Local Directory (LDN) Number
For ISDN dial backup, the LDN is stored in Stored Number 10.
Table 9-1. AT Commands for Storing Phone Numbers
AT Command
Description
&Zn=
Store Phone Number
&Z9=
Enter SPID Number for ISDN dial backup
&Z10=
Edit LDN for ISDN dial backup
9.2 SW56 Auto Answer
The SW56 Auto Answer option is used to specify how incoming calls are to
be answered. If ENABLED, incoming calls are automatically answered by the
CSU/DSU MS DBU. If DISABLED, an incoming call can be answered manually,
by an AT or V.25 command from the DTE, or by raising TR from the DTE.