I think it's only to increase the sound of the horn to be able to here it in the loud traffic noise also.
DS3 is 44.7 Mbps and a T1 is 1.55 Mbps. So 1 DS3 = 28 T1s http://www.dslbroker.com/ds3.html
A DS3 has 28 T1's http://techblog.intelletrace.com/what-is-a-ds3-hub/
3 ds3 in stm1
A DS3 can do 45Mbps Bidirectional Simultaneously.
how many DS3's are in an OC192
an OC48 has 48 DS3's.
672 DS0 make 1 DS3
T3 is the same as DS3. DS3 is a 45Mbps Data Circuit
T3 is the same as DS3. DS3 is a 45Mbps Data Circuit
A DS3 can do 45Mbps Bidirectional Simultaneously. That is 5.63 MBps
24 DS0 make 1 DS1 28 DS1 make 1 DS3 672 DS0 make 1 DS3