Fabrizio replied to the topic 'indi_celestron_aux' in the forum. 2 years ago

In my experience is hard to distinguish between different types of USB/Serial converters from product description. 99% of low cost converters claims RS232 compatibility but they have a TTL interface (0,+5v) that works only with the so-called "TTL tolerant RS232". In our case, they can be only used for the AUX interface. For all the other mount interfaces a "quasi-https://indilib.org/telescopes/celestron/celestron-aux-driver.htmltrue" USB/RS232 converter (-5,+5v swing ) is sufficient.
Below there is a copy taken from indilib.org/telescopes/celestron/celestron-aux-driver.html of the specification of each interface of Celestron scopes, including the required voltage swing.

  1. HC: serial cable connected to hand controller serial port (less recent models).
    • 4 pins connector (RJ11).
    • 3 wires used: GND, TX, RX.
    • RS-232 serial voltage levels (+5V,-5V).
    • 9600 baud transmission speed.
    • No transmission flow handshake, no echo.
    • Command protocol: pass through (mostly AUX protocol encapsulated inside HC messages).
  2. HC: USB cable connected to hand controller USB port (most recent models) (alpha testing).
    • mini USB connector.
    • Command protocol: pass through (mostly AUX protocol encapsulated inside HC messages).
  3. AUX: serial cable connected to Celestron AUX port.
    • 6 pins connector (RJ12)
    • 5 wires used: GND, TX, RX, CTS, RTS
    • TTL serial voltage levels (+5V, 0V)
    • 19200 baud transmission speed
    • Half duplex CTS/RTS handshake with echo
    • Command protocol:  AUX
  4. PC: serial cable connected to Celestron PC port
    • 8 pins connector (RJ45)
    • 5 wires used: GND, TX, RX, CTS, RTS
    • RS-232 serial voltage levels (+5V,-5V)
    • 19200 baud transmission speed
    • Half duplex CTS/RTS handshake with echo
    • Command protocol: AUX
  5. USB: USB cable connected to an USB port of telescope mount (alpha testing).
    • USB connector type A.
    • Command protocol: AUX .


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