• Yaesu DTMF Mic YM-48

    From G8MNY@21:5/101 to TECH on Wed Aug 7 06:10:12 2019
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    From: G8MNY@GB7CIP.#32.GBR.EURO
    To : TECH@WW

    By G8MNY (Revamp Nov 08)
    (8 Bit ASCII graphics use code page 437 or 850, Terminal Font)

    I use mine with FT790/690/290 for DTMF control of a repeaters etc.

    This is the diagram of the mic, I reverse engineered it ...

    ┌─────────────────────────────────┬───────────┬───────┬────┬────────>+5v rd
    │ 4x 1n │ │ 47u=== ===220u pin 4
    │ Keyboard ┌───┬───┬───┬──)───────────)───────┴────┤
    │ Matrix rd === === === === │ │ │ ___ UP ye/bn
    │ 1┼─2─┼─3─┼─A─┼───)───)───)───┤ │ │ ├─o o────>pin 6
    │ │ │ │ │ bn│ │ │ │ │ │ wh│
    │ 4┼─5─┼─6─┼─B─┼───)───)───┤ │ │ │ │ ___ DOWN bk/bl
    │ │ │ │ │ or│ │ │ │ │ │ ├─o o────>pin 7
    │ 7┼─8─┼─9─┼─C─┼───)───┤ │ │ │ 3.52 │ │
    │ │ │ │ │ ye│ │ │ │ │ MHz │ │ ___ PTT bk
    │ *┼─0─┼─#─┼─D─┼───┤ │ │ │ │ ┌┤[]├┐ │ bn├─o o────>pin 3
    │ v│ g│ b│ w│ ┌─┴───┴───┴───┴──┴─┴────┴┐ │ │
    │ i│ n│ k│ h├─┤9 14 13 12 11 1 7 osc8│ 47 │
    │ │ │ ├───)─┤5 c row DTMF IC │ │ │
    │ │ ├───)───)─┤4 o 8202 o/p │ │ 220u │
    │ ├───)───)───)─┤31 l 10 6 16 │ ├────┤├──────┤
    │ === === === ===└─────┬─────┬─────┬──────┘ │/ + │
    │ └───┴───┴───┤ 15k │ ├────2k2─┤ │
    │ 4x 1n │ _│_ │ │ │\e DTMF │
    2k2 │ / \e │ │ └─12───LS────┤
    │ │ │ └───┤ │ rd bk │
    │ u1 │ │ mute │ │ │ MIC wh
    ├───┬────┤├────)─────┴───────)─────)──100───────┬────100───)────────>pin 2
    │ │ │ │ │ │ │
    Mic === + │ │ ├───┤├─47k─>3k3 DTMF │
    │ │1n │ │ 10k +1u │ LEVEL │ Screen
    └───┴──────────┴─────────────┴─────┴────────────┴──────────┴────────>Pin 1

    Here the UP & DOWN button are connected to earth, but they can be to +5V for some rigs! So check your rig handbook to see which it needs.

    DTMF SY
    his uses two pure sine wave tones controlled from a 4x4 keypad matrix, a low-

    frequency tone & a high-frequency tone, to specify 1 of the 16 options.

    Pressing 2 keys in the same row/column, normal results in a single tone.

    TONE HIGH 1209Hz 1336Hz 1477Hz 1633Hz
    LOW
    697 Hz 1 2 3 A
    770 Hz 4 5 6 B
    852 Hz 7 8 9 C
    941 Hz * 0 # D

    Frequency tolerance: ±1.5%

    The 2 tones must not clip & mix on the Tx/RF path/Rx as the DTMF Rx IC uses the presence of more than 2 tones to identify the signal non DTMF & ignores it.


    Why Don't U send an interesting bul?

    73 de John G8MNY @ GB7CIP



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