| | CLASS NOTES |
| 1 | DF | DIAGNOSTIC TESTING, MALFUNCTION INDICATION, OR ELECTRICAL CONDITION MEASUREMENT {12} |
| 34 | DF | SERVICE MONITORING OR OBSERVATION {1} |
| 36 | DF | FREE CALLING FROM PAYSTATION |
| 37 | DF | EMERGENCY OR ALARM COMMUNICATIONS (E.G., WATCHMAN'S CIRCUIT) {9} |
| 52 | DF | INCLUDING AID FOR HANDICAPPED USER (E.G., VISUAL, TACTILE, HEARING AID COUPLING) |
| 55.1 | DF | HAVING NEAR FIELD LINK (E.G., CAPACITIVE, INDUCTIVE) |
| 56.1 | DF | HAVING LIGHT WAVE OR ULTRASONIC LINK FOR SPEECH OR PAGING SIGNAL {2} |
| 67.1 | DF | AUDIO MESSAGE STORAGE, RETRIEVAL, OR SYNTHESIS {13} |
| 90.01 | DF | TELEPHONE LINE OR SYSTEM COMBINED WITH DIVERSE ELECTRICAL SYSTEM OR SIGNALLING (E.G., COMPOSITE) {8} |
| 110.01 | DF | COMPOSITE SUBSTATION OR TERMINAL (E.G., HAVING CALCULATOR, RADIO) |
| 111 | DF | WITH USAGE MEASUREMENT (E.G., CALL OR TRAFFIC REGISTER) {3} |
| 142 | DF | WITH CALLING NUMBER DISPLAY OR RECORDING AT CALLED SUBSTATION |
| 143 | DF | WITH CHECK OPERATED CONTROL (E.G., PAYSTATION) {5} |
| 156 | DF | MULTI-LINE OR KEY SUBSTATION SYSTEM WITH SELECTIVE SWITCHING AND CENTRAL SWITCHING OFFICE CONNECTION {7} |
| 167 | DF | PRIVATE (E.G., HOUSE OR INTERCOM) OR SINGLE LINE SYSTEM {6} |
| 177 | DF | POLYSTATION LINE SYSTEM (I.E., PARTY LINE) {6} |
| 188 | DF | CALL OR TERMINAL ACCESS ALARM OR CONTROL {5} |
| 201 | DF | SPECIAL SERVICES {9} |
| 219 | DF | PLURAL EXCHANGE NETWORK OR INTERCONNECTION {6} |
| 242 | DF | CENTRALIZED SWITCHING SYSTEM {15} |
| 333 | DF | CONCENTRATOR OR TRUNK SELECTOR {4} |
| 338 | DF | REPEATER (E.G., VOICE FREQUENCY) {9} |
| 350 | DF | SUPERVISORY OR CONTROL LINE SIGNALLING {5} |
| 387 | DF | SUBSTATION OR TERMINAL CIRCUITRY {7} |
| 398 | DF | LINE EQUALIZATION OR IMPEDANCE MATCHING |
| 399 | DF | SUBSCRIBER LINE OR TRANSMISSION LINE INTERFACE {5} |
| 414 | DF | TRANSMISSION LINE CONDITIONING {2} |
| 418 | DF | CALL SIGNAL GENERATING (E.G., RINGING OR TONE GENERATOR) |
| 419 | DF | TERMINAL {4} |
| 441 | DF | TERMINAL ACCESSORY OR AUXILIARY EQUIPMENT {9} |
| 457 | DF | MISCELLANEOUS |
| | ********************************** |
| | CROSS REFERENCE ART COLLECTIONS |
| | ********************************* |
| 900 | DF | INTERNET (e.g., Internet phone, webphone, Internet-based telephony) |
| 901 | DF | VIRTUAL NETWORKS OR VIRTUAL PRIVATE NETWORKS |
| 902 | DF | AUTO-SWITCH FOR AN INCOMING VOICE DATA, OR FAX TELEPHONE CALL (E.G., COMP/ FAX/TEL) |
| 903 | DF | PASSWORD |
| 904 | DF | AUTO-CALLING |
| 905 | DF | FAX MAIL |
| 906 | DF | TOUCHTONE MESSAGE TRANSMISSION |
| 907 | DF | SPEECH RECOGNITION VIA TELEPHONE SYSTEM OR COMPONENT {1} |
| 909 | DF | ALTERNATIVES |
| 910 | DF | BAR CODE OR OPTICAL CHARACTER READER WITH TELEPHONE |
| 911 | DF | DISTINCTIVE RINGING |
| 912 | DF | GEOGRAPHICALLY ADAPTIVE |
| 913 | DF | PERSON LOCATOR OR PERSON-SPECIFIC |
| 914 | DF | PROGRAMMABLE TELEPHONE COMPONENT {1} |
| 916 | DF | TOUCH SCREEN ASSOCIATED WITH TELEPHONE SET |
| 917 | DF | VOICE MENUS |
| | ********************************* |
| | FOREIGN ART COLLECTIONS |
| | ********************************* |
| FOR 100 | DF | HAVING NEAR FIELD LINK (E.G., CAPACITIVE, INDUCTIVE) (379/55) |
| FOR 101 | DF | HAVING ELECTROMAGNETIC LINK FOR SPEECH OR PAGING SIGNAL (E.G., LIGHT WAVE LINK) (379/56) {2} |
| FOR 109 | DF | HAVING SINGLE CHANNEL TELEPHONE CARRIER (379/64) {2} |
| FOR 112 | DF | TELEPHONE LINE OR SYSTEM COMBINED WITH DIVERSE ELECTRICAL SYSTEM OR SIGNALLING (E.G., COMPOSITE) (379/90) {8} |
| FOR 132 | DF | COMPOSITE SUBSTATION OR TERMINAL (E.G., HAVING CALCULATOR, RADIO) (379/110) |
| FOR 133 | DF | WITH AUDIO MESSAGE STORAGE AND RETRIEVAL (379/67) {1} |
