H.324 protocols define standards to be used for low speed video conferencing over analog lines, "Plain Old Telephone Service" (POTS), and on 64-128 kbps ISDN.
The picture quality over analog (POTS) connections is significantly less than ISDN and T-1 connections. However, when ISDN is not available, or the price is prohibitive, the ability to have visual connections over analog lines is very exciting.
Applications for such equipment include: