ZETRON 4000 Series, Installation Manual

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167
Wiring the Dispatch Consoles
receive audio. The Select Audio Out connection for the recorder output is shown in Table
70 .
Microphone Push-To-Talk Implementation
The console features two microphone ports. One port is for high-level electret element
microphones, such as handsets or headsets. The other port accommodates low-level
dynamic element microphones, such as desk mics or gooseneck mics.
The console automatically chooses the proper microphone port using several external
signals. These signals are the PTT associated with the dynamic mic port, the PTT for the
electret mic port, the Hookswitch signal and mic switch signal (previously know as “Spare
Input #9”).
Microphone Steering Note
There are three ways to cause the console to transmit: grounding the electret port PTT
signal, grounding the dynamic port PTT signal, and pressing a “soft” (programmable)
console transmit key. Soft transmit keys are keys programmed using the CPSW. These are
keys such as “instant xmit”, “site intercom”, and “console intercom”, which appear on the
console or console expanders.
CPSW may be used to determine the microphone audio source when soft keys are used.
Four options are available:
• Always use the dynamic mic port
• Always use the electret mic port
• Use the mic port indicated by the mic switch (“Spare Input #9”) signal
• Use the port indicated by the “Hookswitch” signal
For the third option, shorting the mic switch to ground causes the soft transmit keys to use
the electret port (handset or headset). Opening the mic switch from ground will cause the
soft transmit keys to use the dynamic port (desk mic or gooseneck mic). This option is
normally programmed at the factory for systems, which use the Telephone Radio Headset
Interface (TRHI).
For the fourth option, shorting “Hook” to “Hookswitch –” (by lifting the handset
from the cradle or plugging a headset into its jack) will force the soft transmit keys to use
the electret port (handset or headset). Opening “Hook” from “Hookswitch –” (by
placing handset on its cradle or removing the headset from its jack) will force the soft
transmit keys to use the dynamic port (gooseneck or desk mic). The Hookswitch steered
audio source is the normally supplied factory default when the TRHI is not attached.
The hookswitch signal always re-routes received audio between the console speaker and
the headset/handset. This is in effect a “speaker switch” signal. When “Hook” is
shorted to “Hookswitch -” (ground), the received audio is routed to the headset/handset
earpiece. When “Hook” is opened from “Hookswitch -” the received audio is