EuropeanDigital telephones: 3110, 3310, and 3820 Page331 of 544
Option11C and 11C Mini TechnicalReference Guide
Alerting tone characteristics
The tone frequency combinations are as follows:
A 500 Hz buzz signal is provided for incoming call notification while the
receiver is off-hook.
Power requirements
The Meridian digital telephones are loop powered. Loop power, originating
in the ISDLC or the DLC, consists of a 30 Vdc power source and assumes a
3500ft. (1219 m) maximum loop length of 24 AWG (0.5 mm) wire and a
minimum 15.5Vdc at the telephone terminals.
Note: The loop length limit is defined by a 15.5 dB loss at 256 KHz.
Longer lengths can be determined using the wire’s gauge and insulation.
Some configurations of telephones and options need more than basic loop
power to operate. Table101 lists the types of Meridian digital telephones and
shows when additional power is needed to operate the telephone or its
optional hardware. Power Supply Boards come installed in factory-
assembled configurations that require additional power.
Note: If a power failure occurs, configurations that require loop power
will continue to work only if the system has battery backup. Only those
options that require additional power will cease to function.
Tone Frequencies Warble Rate (Hz)
1667 Hz, 500 Hz 5.2
2667 Hz, 500 Hz 2.6
:
31600 Hz, 2000 Hz 5.2
41600 Hz, 2000 Hz 2.6
:
3333 Hz, 250 Hz 5.2
4333 Hz, 250 Hz 2.6