
| 
 | 
 | 
 | 
 | 
 | 
 | 
 | Shield | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | Relay Outputs | 
 | 
 | 
 | 
 | Clock Inputs or Remote Control | 
 | ||||||
| 
 | Power Input | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | Mic Only | 
 | 
 | 
 | 
 | 
 | 
 | 
 | |||||||||||
| 
 | 
 | 
 | 
 | Line In | 
 | Output | 
 | Line Out | 
 | Mic Only | NO | 
 | 
 | NO | 
 | NO | 
 | 
 | NO | 
 | ||||||||||
| Model  | Telco In | 
 | 
 | 
 | 
 | 
 | 
 | NC | NC | 
 | NC | 
 | NC | 
 | 
 | 
 | 
 | 
 | 
 | |||||||||||
| 24 Volts AC | 
 | 
 | + | - | Level | + | - C1 | 
 | 
 | 
 | 1 | C | 
 | 1 | C | 1 | C | 
 | 1 | C | NO | C | NO C | NO C | NO C | NO | C | |||
| 
 | Loop Start | C1 | G | 
 | 
 | C | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 1 | 
 | 1 | 1 | 1 | 1 | 
 | |||||
Figure 1-1.  Back View
| 
 | 
 | Noise Level | Paging Level | ||||||||
| 
 | dB SPL | 
 | 
 | dB | |||||||
| 
 | 100dB | 
 | 
 | 
 | 105dB | 
 | 
 | 
 | 
 | Full Volume | |
| Manual Level Control | 
 | 
 | 
 | 95dB | 
 | 
 | 
 | 
 | |||
| 
 | 
 | 
 | 
 | 
 | 
 | 
 | |||||
| 90dB | 
 | 
 | 
 | 
 | 
 | 
 | 
 | ||||
| 
 | 
 | 
 | 
 | ||||||||
| 
 | 
 | 
 | 
 | 
 | 85dB | 
 | 
 | 
 | 
 | ||
| 
 | 
 | 80dB | 
 | 
 | 
 | 
 | 
 | 
 | 
 | ||
| 
 | 
 | 
 | 
 | 
 | 75dB | 
 | 
 | 
 | 
 | ||
| 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | |||
| 
 | 
 | 70dB | 
 | 
 | 
 | 
 | 
 | 
 | 
 | ||
| 
 | 
 | 
 | 
 | 
 | 65dB | 
 | 
 | 
 | 
 | ||
| 
 | 
 | 60dB | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
| 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | |
| 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
Set Maximum Noise Level
95dB
90dB100dB
85dB
105dB
Power
| Automatic Level Control | Telephone Input Active | 
Figure 1-2.  Front View
| 
 | 4 to | 0 to 5 Volt | LED | LED | 4 Volume | 
| 
 | Control | ||||
| 
 | 20 Mil | 
 | |||
| 
 | 
 | Driver | Display | ||
| 
 | Rec. | 
 | |||
| 
 | 
 | 
 | 
 | for High | |
| 
 | 
 | 
 | 
 | 
 | Noise Level | 
| 0 DBM | 
 | 
 | 4 Bit | 4 Bit | Clock | 
| 
 | 
 | Converter | Converter | Inputs | |
| 
 | 
 | 
 | |||
| 
 | 
 | Audio | 
 | 
 | FP Manual | 
| 
 | 
 | Detect | 
 | 
 | |
| 
 | 
 | Micro | 
 | or Automatic | |
| C1 | 
 | Gain Hold | 
 | ||
| 
 | 
 | Level | |||
| 
 | 
 | 68HC705 | 
 | ||
| 
 | 
 | 
 | 
 | Control | |
| G | 
 | 
 | 
 | 
 | Selection | 
| 
 | 
 | 
 | One of 8 | 
 | 600 Ohm | 
| X 1 Buffer | 
 | 
 | 0 dB | X 1 Buffer | 600 Ohm | 
| AGC | 
 | Bal line | |||
| 
 | 
 | 
 | or Level | Bal line | |
| 
 | 
 | 
 | 
 | Driver | |
| 
 | 
 | 
 | Set | Driver | |
| 
 | 
 | 
 | 
 | 
 | |
| 
 | 
 | 
 | 
 | FP | |
| 
 | 
 | 
 | 
 | Selector | |
| 
 | 
 | 
 | 
 | 
 | |
| 
 | 
 | 
 | 
 | for Max. | |
| 
 | 
 | 
 | 
 | Noise | |
| Loop St | 
 | 
 | 
 | 
 | |
| 
 | 
 | 
 | 
 | 
 | |
| 
 | 
 | 
 | 
 | 
 | FP PA | 
| 
 | 
 | 
 | 
 | 
 | Level | 
| 
 | 
 | 
 | 
 | 
 | Display | 
Figure 1-3.  Ambient Level Controller Block Diagram
Overview 
