7
LIMITED-DISTANCE MODEM 56/64
1. Specifications
Data Rates
—56 or 64 kbps, selectable
Number of Data Bits (Async Mode)
—8, 9, 10, or 11,
including 1 start and 1 stop bit, with or without
parity
Frequency Allowance (Async Mode)
—Shortening
of the stop bit on the receive end is selectable:
• 12.5% allows a frequency difference between the
async DTE and the Modem of -2.5% to +1.0%
• 25% allows a frequency difference of -2.5% to
+2.3%
Transmission Line
—4-wire unconditioned
dedicated line (two twisted pairs)
Transmission Mode
—Sync or Async, full-duplex
Transmission Controls
—
• DCD (Circuit 109) turns ON after recognizing
a receive signal from the line.
