 Some TV signal systems used a low-speed modem on the phone line for menu operation.The resulting system was rolled out in several test studies, all of which were failures.The use of the 202 model modem, rather than one compatible with the existing DATAPAC dial-up points such as the Bell 212, created severe limitations, as it made use of the nationwide X.25 packet network essentially out-of-bounds for Telidon-based services.