On-hold music is considered standard in business phone systems today because people actually perceived wait times as shorter when they hear it. On-hold music traditionally worked by having specialized equipment attached to the phone, and the jack might plug into the radio, then tapes, then CDs, then MP3 players. PRI boards are built with jacks to play on-hold music.
Different types of music elicit different reactions in the human brain. Make sure you pick the right one for your business.

message. Important notice. Since the phones can be used anywhere in the world, Emergency 911 will not always work as intended. If the phone system is in Reno and the desk phone is in Phoenix and you dial 911, Reno will get the ambulance. In those cases, we try to have stickers on phone that say “No 911” but they wear off or may not have
It depends on your business industry, type of callers and marketing plan. Assuming that you take a profit driven approach to using your telephone on hold messages as a marketing tool, you will want to consider changing at a minimum of twice per year, however its best to be more proactive and update more often like quarterly or even monthly. Callers love something new and refreshing (don’t we all!), particularly those that frequently call back and are placed on hold! Why not inform them them of special promotions, new products, or customer service info – there’s always something more that can be said! Make the most of your telephone’s on hold messaging infrastructure. It is an effective way to win, retain, and sell your callers on hold.