Oki OKIFAX4550 Maintenance Manual page 362

F Off-hook detectors (IC5)
These circuits detect the off-hook state of the telephone connected to the TEL.
G Impedance switches (CN15 to CN35)
These circuits set the impedance according to the line requirement.
220: 220 ohm + 820 ohm//115 nF (CN15)
370: 370 ohm + 620 ohm//310 nF (CN35)
600: 600 ohm (CN25)
I
Ring impedance switches (S1-1, 2)
These switches set the ring impedance according to the line requirement.
41309401TH Rev.4
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