The #1 & #2 uniselectors below, are now wired ready to signal a subscriber connecting via tranmission bus #1 or #2.
Uniselector positions (uniselector #1 & #2)
24
23
22
21
20
19
18
17
16
15
14 N/Unobtainable (Australian PMG 400Hz - 2.5on/0.5off)
13 Ring Tone (Australia PMG 400/16Hz 0.4on/0.2off /0.4on/2.0off)
12 Busy Tone (Australian PMG 0.375on 0.375off)
11 Spare (not allocated)
10 Services Dial Tone (Australian PMG 33 1/3Hz continuous)
9 Spare (not allocated)
8 Destinctive Ring Tone (US Bell System 440/480Hz 4on/2off)
7 Spare (not allocated)
6 Special Signalling Tone [425Hz continuous] software driven cadence
5 Time, Trunk dialing signalling [900Hz continuous] software driven cadence
4 Dial Tone (Australian Telstra standard 425Hz~25Hz continuous)
3 Spare (not allocated)
2 Spare (not allocated)
1 Call Waiting (Australian PMG Public Telephone 0.075on/0.15off/0.075on/2.70off)
0 Home Position
The generators above provide the Dial Tone (425/25), 425Hz & 900Hz Tones plus US Bell system Ring Tone. The Australian PMG standard Dynamotor provides the rest .
.... and the oscillator output balancing transformers below (x12) provide isolation from the transmission path & audio level presets to match up all the tones.
The 486 is now built up and ready to take control :)
Operator....
