NEW YORK ( TheStreet) -- Garmin ( GRMN) took a wrong turn into smartphones and looks to be exiting by year's end. The GPS navigation device maker and its Taiwan-based hardware partner Asustek are ending a joint phone-making venture in January, according to a report in DigiTimes Monday. Garmin wasn't immediately available for comment. Garmin and Asus made the Garminfone for Deutsche Telekom's ( DT) T-Mobile, hoping the marriage of portable navigation devices and phones would give Garmin a new growth market. But sales of the Garminfone have been weak. Last month, Garmin CFO Kevin Rauckman warned that disappointing sales had caused the company to consider ending its phone effort. The company said phone sales in the second quarter totaled $27 million, which were below expectations. Garmin's story highlights the difficulties of competing in the smartphone market where giants like Apple ( AAPL), Google ( GOOG), Research In Motion ( RIMM) and Nokia ( NOK) already offer navigation services on phones. Asus, a major computer and notebook manufacturer, is expected refocus its mobile effort back on its own smartphones, according to the DigiTimes report. --Written by Scott Moritz in New York. >To contact this writer, click here: Scott Moritz, or email: firstname.lastname@example.org. To follow Scott on Twitter, go to http://twitter.com/TheStreet_Tech. >To send a tip, email: email@example.com.