AT&T Communications System Ringing Patterns, Groups 2448 System, Indicator Light Patterns

Ringing Patterns

Two short rings—call from outside system

One long ring—call from another intercom extension

One short, one long ring—transferred call

Three short rings—transfer return or line reserve callback (or auto callback on a 2448 system)

One low-volume ring pattern—call when your telephone is busy (or calls are forwarded on a 2448 system)

Groups (2448 System)

Telephones in 2448 systems are assigned to

groups according to their intercom extension numbers.

Intercom Extension Numbers	Group Number
10-17	61
18-25	62
26-33	63
34-41	64
42-49	65
50-57	66

Indicator Light Patterns

I USE (The telephone line you are currently using)

THEY USE (The telephone line someone else IS currently using)

RINGING (A telephone line that is ringing normally)

CALLBACK SIGNAL (The system is calling you for a line reserve callback or transfer return)

I HOLD (A telephone line that you have placed on HOLD)

THEY HOLD (A telephone line that someone else has placed on HOLD)

Very Long On, Short Off, repeat

Steady On

Long On, Long Off, repeat

Short On, Short Off, repeat

One Short Flash, Very Long Off, repeat

Two Short Flashes, Very Long Off, repeat

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