Specifications

1.7.2 System Ringing Patterns
Ring Type Ring Cadence
CO/PBX Line Ring Host system ring cadence
Intercom Tone Signaling Two 150 msec. tone bursts every four seconds
Voice Signaling alert One 215 msec. tone burst
Timed hold recall at station that put call on hold Three 150 msec. tone bursts at the end of each timeout
period
Call back alert One 80 msec. tone burst followed by three 150 msec. tone
bursts and one 80 msec. tone burst
Queue Enabled
Call forward alert One 80 msec. tone burst
Transfer ringing Two 1.1 sec tone busts every four seconds
Tone Type Tone Cadence
Dial Tone Continuous on
Called station ring-back One sec. on and three sec. off
Base level program entry 80 msec. tone burst sounded once
Error tone—incorrect entry 530 msec. tone burst sounded three times
All-call and zone paging notification tone 80 msec. tone burst followed by 280 msec. tone
Busy tone
530 msec. tones sounded continuously
Override feature not allowed
Night transfer feature not allowed
Call waiting tone Three 80 msec. tone bursts sounded once
Called station in do-not-disturb mode 140 msec. tone burst sounded twice every 1.5 sec.
Call-back busy feature on 260 msec. tone burst sounded once
System is awaiting memory dial number or key mapping
entry after location is specified
80 msec. tone burst sounded continuously
Override feature on warning tone
Six 100 msec. tone bursts sounded for 1.5 secs.
SOHVA tone
DISD ringback tone Dual 440/480 Hz tone sounded 1 sec. on/1 sec. off
DISD dial tone 381 Hz tone sounded continuously
DISD confirmation tone Two 125 sec. bursts of 381 Hz tone sounded once
DISD busy/error tone Three 500 msec. bursts of 381 Hz tone sounded once
IMI66–132 DSU II Digital Telephone System
1–26 Introducing The DSU II Digital Telephone System