The B149 and B159 analog phones need to use a flash hook time in the same range as that being used by the IP Office. That default values the IP Office uses depend on its system locale, refer to the "IP Office Locale Settings Reference" manual. However, individual extensions can be configured separately (see Extension | Analogue | Flash Hook Pulse Width). The setting can be tested by making a call to another extension during which pressing should toggle the call on hold and back if the flash hook time is set correctly.
1.Press the Menu button.
2.Scroll to SETTINGS and press OK.
3.Scroll to FLASH and press OK.
4.Select a value that falls in the range set in the IP Office configuration for the extension and press OK.
5.To exit the menus, press Menu again. To exit the current menu option, press .