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DCE Assembly Rev2 P560 720px.jpg


  • TTL to RS-232 converter
    • Tx/RX/RTS/CTS
  • Female DB-9 connector
  • FTDI pinout (reversed directions to directly connect to FTDI Interface)
  • Up to 115,200 baud @ 5V
  • Up to 250,000 baud @ 3.3V
  • 49x49mm card
  • 4x 4-40 holes

DCE - RS-232 to TTL

  • The DCE (peripheral) has the female DB-9 connector


  • The DTE (PC) has the male DB-9 connector


H1 Connector

  • Pins signal directions are reversed from an FTDI card
    • Can be directly wired to FTDI connector


  1. GND
  2. CTS (out)
  3. VCC (3.3V or 5V)
  4. TX (in)
  5. Rx (out)
  6. RTS (in)

H2 - Power

  • 2x4 right angle header (optional)

Test Procedure

DCE DTE Test P554 720px.jpg

  • FTDI-49MM
    • 3.3V/5V jumper set to 5V
    • Power cable from FTDI-49MM 5V Connector split to both DCE/DTE cards
  • DCE/DTE Cards
    • 9 pin connectors plugged together
  • FTDI loopback cable
    • TX/RX connected
    • RTSCTS connected
  • USB B cable to PC
  • Run PuTTY
    • 115,200 baud, RTS/CTS
  • Type and it comes back

SP232A Application

SP232A app.PNG

DTE (reference)

DCE Assembly Sheet