TABLE 13 LOCAL TRANSMISSION TECHNOLOGY (BELL OPERATING COMPANIES) MAJOR INTEROFFICE TRANSMISSION LINKS YEAR END TOTAL COPPER FIBER RADIO 1990 2,895,117 1,092,041 37.7% ###### 60.0% 65,092 2.2 % 1991 3,283,956 1,048,545 31.9 ###### 65.6 81,368 2.5 1992 3,570,147 869,052 24.3 ###### 73.1 90,910 2.5 1993 4,020,454 803,035 20.0 ###### 77.8 90,682 2.3 1994 4,520,274 569,428 12.6 ###### 85.0 107,432 2.4 WORKING TELECOMMUNICATIONS CHANNELS YEAR END TOTAL COPPER FIBER OTHER 1990 ###### * ###### 86.8% ###### 2.9 % 0 0.0 % 1991 ###### ###### 96.1 ###### 3.9 2,347 0.0 1992 ###### ###### 94.8 ###### 5.2 238 0.0 1993 ###### ###### 93.6 ###### 6.4 1,427 0.0 1994 ###### ###### 92.3 ###### 7.7 1,440 0.0 SOURCE: 1990-94 REPORTED IN ARMIS 43-07. * INCLUDES SOME OTHER CHANNELS.