Netopia R7100-C User Reference Manual page 242

G-2 User's Reference Guide
Because over 300,000 lines are already deployed using HDSL, service providers feel comfortable with SDSL
since it uses the same technology as its predecessor and ISDN. The line coding employed by both HDSL and
ISDN has not caused any interference with existing services like T1. This means service providers deploy SDSL
solutions without worry about impact on other services in neighboring binder groups.