Control Data Corporation INFORMATION SYSTEMS TERMINAL II Hardware Maintenance Manual page 25

INTERNAL MODEM
The internal modern PC board is a FSK (Frequency Shift Key)
data modern designed for asynchronous operation on a voice-
grade telephone line. Features are:
• RS-232-C interface to the terminal for transmitted
and received data
• Forward (receive) channel l300-Hz mark, 2l00-Hz
space binary, FSK modulated signal
• Reverse (transmit) channel 390-Hz mark, 490-Hz space
binary FSK modulated signal.
• Receive data rate up to 1200 bps
• Transmit data rate 0 to 150 bps
• Line impedance is 600 ohms balanced
on unconditioned
dial-up line
• Operation is full duplex on a two-wire, dial-up line
• Transmitter output level is -9 dBm (+0, -4 dBm)
• Receiver input level is from -10 dBm to -43 dBm
POWER SUPPLY
The basic power supply is designed for l20-V ac, SO/60-Hz,
or 220/240-V ac, SO/60-Hz input. However, the 220/240-volt
operation requires a different ac entry panel. Regulated
output voltages generated are:
• +55 volts
• +12 volts
• +5 volts
• -5 volts
• -12 volts
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