4824/Sync-Up (4,800 bps Bell 208 and 2,400 bps Bell 201c)

This is a fully operational modem, but it's a used product and sold as is

  4,800 or 2,400 bps synchronous operation over PSTN or Private line environments 
  Strappable to operate over either 2-wire dial-up or 4-wire leased lines
  IBM PC/XT/AT bus compatible
  Software selectable options
  Automatic pulse or tone dialing
  Call progress detection
  Bell 208a, 208b and Bell 201c compatible
  Built-in diagnostic testing

 SPECIFICATIONS (most shown for the 4800 side of modem)

  Data Rate: 4800 bps or 2400 bps, synchronous
  Operation: Half-duplex over 2-wire PSTN or private lines; Full duplex over 4-wire private lines
  Operating Mode: Manual Answer, Automatic Answer, Manual Dial, Automatic Dial
  Modulation: Differential Phase Shift Keyed (DPSK)
  Carrier Frequency: 1800 Hz
  Answer Back Tone: 2025 Hz, 3 seconds duration
  Transmitter Output Level: Permissive or Programmable
  Clear to Send Delay: 8.5 ms, 50 ms, or 150 ms, or 600 ms (selectable)
  Digital Interface: IBM PC bus, and RS-232
  Selectable Interrupts and I/O Address: IRQ 2, 3, 4 and 5; Addresses 300, 310, 340, and 360
  Receive Level: -44 " 2 dBm or -34 " 2 dBm (selectable)
  Transmit and Receive Clock: 4800 Hz
  Pulse Dialing Rate: 40% Make, 60% Break; Inter-digit Time: 75 sec.
  Tone Dialing Duration: 70 ms ON; 70 ms OFF
  Environmental: 0 to 50^o C; Humidity: 0 to 95% non-condensing; Altitude: 0 to 10,000'  
  Power Requirements: 100 ma " 12 V, 750 ma + 5V
  Certification: FCC Rules, Part 68 certified, FCC Part 15 certified, Canadian DOC (Department of Communications) CS-03 certified.