Your modem is V.250 compatible but it dosn't work with the lift controller.

externes ModemThe development time of modern products is becomming shorter. Many products are produced with an early firmware version inside. The fully developed firmware you have to download from the webside of the producer an update the product before you can use it.

So look at the webside of the modem producer and update the modem if you can find a new firmware there. We recommed to use an industrial modem for the lift controller.