Automatic switching of telegraph messages

Reperforator switching, as used with carrier and radio circuits, has entailed reorganization of the U.S. national network. The equipment is partly automatic, partly manual (push-button switching), but no re-typing is involved. The use of a concentrator (to economize in the number of distributors and the 7-to-5 unit code converter is explained. Automatic facilities for checking message sequence numbers are necessary; the operation of this equipment is followed through.