If you are running a VoIP (Voice over IP) phone system, we can also provide VoIP messages on hold, whereby we only supply the digital content excluding the equipment. If your organisation is only using a single telephone line and not a PBX / PABX multi line phone system, you can still enable your telephone for on hold by connecting to one of
Using the simple tools in Manage & Create, you can craft professional sounding message on-hold productions like these in minutes. > With our Custom Scriptwriter, order professional voiced messages with your choice of voice actor for as little as $25 per message

Website: https://www.alternativetechs.com/wp-content/documents/USER.SV8100_with_SV8100_12-and_24-button_phones.line_keys.pdf
Depending on which ESI phone you have, use the appr opriate diagram (below) to connect it. Each diagram represents the panel on the phone’s underside. Note: The “Top of phone” and “Bottom of phone” references in these diagrams show the correct vertical orientation of the phone — i.e., the part with the display is the top.