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.
The problem, in my mind, is that every single one of these articles misses the point completely. Even if you implemented a call centre system that detected and automatically played someone’s all-time favourite music while they waited, a facility which is possibly not that far off, most music when played down the phone just sounds terrible. Butchering a song that someone actually likes is unlikely to improve the waiting experience.

You have reached {COMPANY NAME}. We will be with you momentarily. Please note your call may be recorded for quality assurance purposes.
As you begin your search for an on hold messages service provider, you’ll find many companies advertising that they can do the job for you. But, you don’t want just any company, nor do you want the same ho-hum, boring hold-music heard at most businesses, because boring is something your business can’t afford to be. You want a provider that adds real value to your bottom line, you want an on hold company that’s responsive to your needs, has a proven track record, and finally, you want a provider that makes the process easy, so you don’t have to!