Analog Display Services Interface

Analog Display Services Interface is a telephony technology that is currently used in POTS or computer-based PBX telephone service. It works in conjunction with a screen-based telephone ("screenphone") or other compatible CPE to provide the user with softkey access to telephone company or internal PBX custom calling features. It is an analog service because it uses analog Frequency Shift Keying (FSK) technology to interact with an LCD screen via short, low-baud rate, downloads to refresh and re-program softkeys in real-time.

The technology introduced and rolled out to RBOCs from Bellcore in April 1995, (very soon after the introduction of CLASS-based services through ESS), was marketed by the RBOCs who implemented it, as a way to streamline all available custom calling options through the use of a screen-based telephone; giving Residential and Small Business telephone subscribers PBX-like functionality at home or in SOHO locations at a significantly lower cost. The service debuted before the onslaught of PCS and VOIP-based telephony technologies became available and was originally slated to also work in conjunction with other types of services such as Enhanced Directory Assistance, telephone banking, movie theatre ticket sales, and other services that could interact with an LCD-screen.

Some of those services did become available later, though, not at the dramatic increase the US-based telephone companies had hoped. Canadian telephone companies such as Telus and Bell Canada, however, had much better luck implementing more ADSI-based services with other industries such as banking, and still markets the service actively (as of 2005).

The service is marketed at telephone customers who subscribe to the majority of CLASS-based services offered by their local telephone company (such as caller ID, Call Return, etc.) by the customization of a telephone capable of providing one-touch access to these features. This greatly increases customer usability by alleviating the need to memorize dialing codes such as *69.

Additionally, a few RBOCs introduced new features such as Call Waiting Deluxe and Message Waiting Indicator to work exclusively with ADSI telephones. The former being perhaps the most involved example of ADSI capabilities and the latter being an example of Visual FSK; another new technology available through CLASS.

The RBOCs who offer this service also restructured their billing of these services into value-based "packages" to stimulate customer interest.