Press the TAB key twice

WAN_set-up
Switch type [NI-1]
Link set-up
Enter Link number 1 and press enter
ISDN set-up
Directory number [enter the ISDN directory number for Link 1 ]
SPID  [enter the ISDN SPID for Link 1 ]

Press the TAB key 2 times

Link set-up
Enter Link number 2 and press enter
ISDN set-up
Directory number [enter the ISDN directory number for Link 2 ]
SPID  [enter the ISDN SPID for Link 2 ]

Press the =  key to return to main menu

Configuration
Connections set-up
Security set-up menu
Security level [ enter Chap or PAP as specified by your ISP]

Press the TAB key once

Remote site set-up menu
Edit Remote site
Enter 'isp' for the 'Remote site id or alias'
Enter 41 for the 'Template id'  (This is the default ISDN template id)

Security Parameters
Outgoing User name [enter the user name provided by your ISP] 
Outgoing PAP password [enter the PAP password provided by your ISP]  or
Outgoing Chap secret [enter the CHAP password provided by your ISP]
Incoming PAP password [enter the incoming PAP password from your ISP]

Press the TAB key

Connection [threshold or dual_link]
Primary connection [ISDN_call]
Secondary connection [ISDN_call]

Connection set-up
ISDN call set-up
ISDN number [enter the primary ISDN number to call your ISP]
Alternate ISDN number [enter the alternate ISDN number to call your ISP]

Press the TAB key

Auto-call [enabled]

Press the TAB key

Protocol set-up
Multilink protocol [enabled]
BACP set-up
BACP [Disabled]

Press the TAB key

IP parameters
NAT enabled [enabled]
IP Routing
Routing protocol [none]
Auto default route [enabled]

Press the TAB key 3 times

Activation set-up
Usage set-up
Usage Limit [unlimited]
Call limit [unlimited]

Press the =  key to return to the main menu

Save configuration
Diagnostics
Soft reset - enter yes

Different methods for connecting to the ISP (apply one of the following 3 methods)
 
Method 1 - For connection on power-up  (this method is already in use by the above configuration example)

Configuration
WAN set-up
Remote site set-up menu
Edit Remote site
Enter the name of your Remote site alias.  In this case,  enter 'isp'.
Connection set-up
Auto-call [enabled]

Press the = key 

Save configuration
DiagnosticsSoft reset -  yes to reset

Note: The above configuration example is already using Method 1 - Automatic call.
If you decide to use Method 2 or Method3, be sure to disable the Auto-call option in the configuration. 

Method 2 - For an On-Demand connection by IP traffic on the local LAN.
Configuration
WAN set-up
IP address connect menu
IP address connect [enabled]
Edit IP address entry
Enter '1' for the IP address connect entry id
Enter '0.0.0.0'  for the IP address
Enter 'isp' for the Remote site alias or id  (same name as your Remote site profile)

 
Method 3 - For a manual call connection.

Configuration
WAN set-up
Remote site set-up menu
Manual call - enter the name of your Remote site alias. In this case, enter 'isp'.