An employee is using a desk phone that is connected only via a network cable. Which of the following technologies is the phone using?

LTE (Long-Term Evolution) is a standard for wireless broadband communication for mobile devices and data terminals, not typically used for wired desk phones.

GSM (Global System for Mobile Communications) is a standard for cellular networks, specifically for mobile phone operation, and is not applicable to a wired desk phone.

VoIP (Voice over IP) is a technology that allows voice communications and multimedia sessions over Internet Protocol (IP) networks, such as the internet or a local area network. A desk phone connected only by a network cable indicates it is an IP phone, utilizing VoIP to send and receive calls.

CDMA (Code Division Multiple Access) is another cellular technology for mobile communication and is also irrelevant to a wired desk phone.