TY - GEN AU - Belinda L Collins AU - William F Danner AU - Robert L Tibbott C2 - , National Institute of Standards and Technology, Gaithersburg, MD DA - 1981-01-01 05:01:00 DO - https://doi.org/10.6028/NBS.IR.81-2428 LA - en PB - , National Institute of Standards and Technology, Gaithersburg, MD PY - 1981 TI - Communication systems for disabled users of buildings: ER -