Channel count functions don't exist in Phidget22 because channels attach individually instead of as one device.
You'll need to use the Phidget Manager class, which has an event handler for whenever a channel attaches. Once the channel is attached, you can use generic Phidget class functions to determine what kind of channel it is and which physical device it belongs to.
For more information see the API documentation
(specifically the Phidget and Manager APIs), and the Manager page
in our documentation.