Specifications

LBI-39100
5
Desk Mic Input for an electret-type microphone similar to part number
19C851086P10 or P11. Approx. input impedance = 600 ohms.
Typical input = 70 mV rms (-21 dBm). Nominal input range =
-27 to -15 dBm. ALC controlled. DC mic bias = 3.7 ±0.5 Vdc
with 1000-ohm load.
Boom or Gooseneck Mic Input for a dynamic microphone similar to Shure Bros. model
VR300 (part number 19C337100P1). Approx. input
impedance = 10K ohms. Typical input = 5 mV rms (-56 dBm).
Nominal input range = -68 to -44 dBm. ALC controlled. No dc
mic bias present.
Line 1, 2, 3 & 4 Balanced 2-wire 600-ohm inputs each designed to receive
voice bandwidth audio from one pair of a 4-wire 600-ohm
twisted-pair transmission system provided by the CEC/IMC.
Transformer isolated. Typical input = 436 mV rms (-5 dBm).
Nominal input range = -20 to +10 dBm. Ground isolation =
greater than 1500 Vdc.
Call Director Patch Balanced 2-wire 600-ohm input designed to accept audio from
a Call Director device similar to Plant Equipment model 3780-
L1-TT-010. Transformer isolated. Typical input = 78 mV rms
(-20 dBm). Nominal input range = -26 to -14 dBm.
Paging Encoder Balanced 2-wire 600-ohm input designed to accept audio from
a paging tone encoder or similar device. Typical input =
436 mV rms (-5 dBm). Nominal input range = -11 to +1 dBm.
Ground isolation = greater than 1500 Vdc.
OTHER INPUTS
Microphone PTT And Monitor Switch Active-low inputs used to detect "dry-contact" switch closures
of the type found in standard microphones, footswitches and
headset jacks. Typical open-circuit voltage = 12 Vdc. Max.
open-circuit voltage = 16 Vdc. Max. short-circuit current = 30
mA. Low-pass filtering prevents undesirable signals such as
switch contact bounce or static charges from triggering
microcontroller circuits; typical microcontroller response
time = input must be valid for greater than 5 milliseconds.
Microphone Sense Active-low inputs used to sense the connection of a
microphone. Typical open-circuit voltage = 12 Vdc. Max.
open-circuit voltage = 16 Vdc. Max. short-circuit current = 30
mA. Low-pass filtering prevents undesirable signals such as
switch contact bounce or static charges from triggering
microcontroller circuits; typical microcontroller response
time = input must be valid for greater than 5 milliseconds.
Page PTT Active-low input used to signal presence of paging signal on
paging audio input. Typical open-circuit voltage = 12 Vdc.
Max. open-circuit voltage = 16 Vdc. Max. short-circuit current
= 30 mA. Low-pass filtering prevents undesirable signals such
as switch contact bounce or static charges from triggering
microcontroller circuits; typical microcontroller response
time = input must be valid for greater than 5 milliseconds.
Call Director Hook Sense & Jack Sense Single-ended logic inputs used to sense CD off-hook and
handset connection status. Each internally pulled to +12 Vdc
via 470-ohm resistor.