Re: Baycom serial module and 300 baud

From: Bob Nielsen (lekzx.yjthiiz@butler.edu)
Date: Tue Jun 26 2001 - 05:51:21 EEST

  • Next message: terhi.victor@logonet.com: "Re: Baycom serial module and 300 baud"

    On Mon, Jun 25, 2001 at 09:58:25AM +0200, Thomas Sailer wrote:
    > Phil schrieb:
    >
    > > Is it possible to use the serial baycom module at 300 baud?
    >
    > Yes. Use "ser3" instead of "ser12" as mode in sethdlc

    As I understand it, this sets the speed of the RS-232 interface, not
    the baud rate of the AFSK signal from the Baycom device to the radio,
    nor can it change from 1000 Hz shift (1200/2200 Hz tones) used with
    1200 baud to the 200 Hz shift (typically 1600 and 1800 Hz, although
    when used with a SSB transmitter, the specific frequencies are not
    critical) used for 300 baud HF packet. IIRC these are all a function of
    the TCM3105 chip used in the Baycom serial modem, therefore not
    software selectable.

    Thus, although you can communicate between the computer and the Baycom
    device at 300 baud, it would still communicate with the radio at 1200
    baud, although with a slower character rate (increased mark dead time).
    It would not be compatible with 300 baud HF packet operation.

    Or do I misunderstand the capabilities of the TCM3105 (or possibly
    Phil's question)?

    73,

    Bob Nielsen, N7XY
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