IBM Series 1 User Manual page 194

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Figure 6-5. output signal electrical circuit
DPC adapter
output driver
TTL open
collector
driver
Twisted-pair
cable
Recommended
termination
+5 volts ± 10%
150 ohms
±
5%
t - -....
--I~ TTL load
300 ohms
±
5%
Ground
Impedance: 100 ohms
Maximum distance: 6.1 m (20 ft)
Ground
Up level
Down level
2.4 V maximum
+0.7 V maximum@ 175 rnA
Figure 6-6. Input signal electrical circuit
DPC adapter
input
termination
+5 volts ± 10%
150 ohms
±
10%
300 ohms
±
2.5%
Ground
Twisted-pair
cable
Impedance: 100 ohms
Maximum distance: 6.1 m (20 ft)
Recommended
customer driver
TTL open
collector driver
(SN75451or
equivalent)
Ground
Down level
+0.6 V maximum
@42mA
customer DPC Adapter
6-13