Hive: HKEY_LOCAL_MACHINE
Key: SYSTEM\CurrentControlSet\Services\RemoteAccess\Parameters
Name: CallbackTime
Type: REG_DWORD
Value: 2-12 seconds
Sets the time interval that the server waits before calling the client back when the Callback feature has been set. Each client communicates the value of its own callback time when connecting to a Remote Access server. This value can be found in the Modem.inf file for the client. If this value is not communicated (that is, if the client does not communicate a value for the callback time, as with Remote Access version 1.0 and 1.1 clients), then the value of the CallbackTime parameter becomes the default. Default=2 seconds.

RAS Tips:

Alert - Win98 2nd Edition now supports 128-bit encyption Q244214
Auditing
Autodisconnect interval
Callback interval
Determine in Logon Script Whether Client Is Connected by RAS or LAN
Disable DUN's Save Password option
FAQs: Dial-Up Networking and RAS Questions technote Q162293
Log connections
log PPP connections
Max unsuccessful logon attempts
Max time limit to successfully logon
NetBIOS gateway
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Remove Dial-up Logon Checkbox
Rings, Control number of rings before RAS server answers
Troubleshooting PPTP Connectivity Issues in Windows NT 4.0Q162847
User Cannot Log On to LAN Because of RAS Logon Failures Q177125