On the hardware side, all telemarketers use computers that have phone support. They either make and take calls using that or have it connected to a phone with digital features. They do this because making phone calls using an internet line is more efficient and affordable. Apart from that, they can also connect a headset, which provides better audio and microphone quality.
All of it also connects to a private branch exchange, or PBX. It allows their computer to switch between an internal network and external calls. It has a switch, essential for distributing calls to different agents and sending outbound ones to their destination.
From there, they have telemarketing software which can be multiple programs or one that integrates all of them (Diabolocom). These include:
Call distribution software: helps queue calls and connect them to open agents.
Interactive voice response (IVR): an IVR acts as a mean to search for initial information automatically for an agent. They have voice recognition and keypad integration.
CRM: a database of client and customer information.
Recording: records conversations to help agents improve and create transparency.