int ai_speed;           /* max conversion period in nanoseconds */
        int qram_len;           /* length of card's channel / gain queue */
        int ao_ability;         /* 0 == no analog out, 1 == basic analog out, 2 == waveform analog out */
-       int ao_n_chan;          /* number of analog out channels */
        const struct comedi_lrange *range_ai;   /* available input ranges */
 };
 
                .ai_speed       = 6250,
                .qram_len       = 256,
                .ao_ability     = 0,
-               .ao_n_chan      = 0,
                .range_ai       = &range_ai_das1801,
        },
        [BOARD_DAS1701ST_DA] = {
                .ai_speed       = 6250,
                .qram_len       = 256,
                .ao_ability     = 1,
-               .ao_n_chan      = 4,
                .range_ai       = &range_ai_das1801,
        },
        [BOARD_DAS1702ST] = {
                .ai_speed       = 6250,
                .qram_len       = 256,
                .ao_ability     = 0,
-               .ao_n_chan      = 0,
                .range_ai       = &range_ai_das1802,
        },
        [BOARD_DAS1702ST_DA] = {
                .ai_speed       = 6250,
                .qram_len       = 256,
                .ao_ability     = 1,
-               .ao_n_chan      = 4,
                .range_ai       = &range_ai_das1802,
        },
        [BOARD_DAS1702HR] = {
                .ai_speed       = 20000,
                .qram_len       = 256,
                .ao_ability     = 0,
-               .ao_n_chan      = 0,
                .range_ai       = &range_ai_das1802,
        },
        [BOARD_DAS1702HR_DA] = {
                .ai_speed       = 20000,
                .qram_len       = 256,
                .ao_ability     = 1,
-               .ao_n_chan      = 2,
                .range_ai       = &range_ai_das1802,
        },
        [BOARD_DAS1701AO] = {
                .ai_speed       = 6250,
                .qram_len       = 256,
                .ao_ability     = 2,
-               .ao_n_chan      = 2,
                .range_ai       = &range_ai_das1801,
        },
        [BOARD_DAS1702AO] = {
                .ai_speed       = 6250,
                .qram_len       = 256,
                .ao_ability     = 2,
-               .ao_n_chan      = 2,
                .range_ai       = &range_ai_das1802,
        },
        [BOARD_DAS1801ST] = {
                .ai_speed       = 3000,
                .qram_len       = 256,
                .ao_ability     = 0,
-               .ao_n_chan      = 0,
                .range_ai       = &range_ai_das1801,
        },
        [BOARD_DAS1801ST_DA] = {
                .ai_speed       = 3000,
                .qram_len       = 256,
                .ao_ability     = 1,
-               .ao_n_chan      = 4,
                .range_ai       = &range_ai_das1801,
        },
        [BOARD_DAS1802ST] = {
                .ai_speed       = 3000,
                .qram_len       = 256,
                .ao_ability     = 0,
-               .ao_n_chan      = 0,
                .range_ai       = &range_ai_das1802,
        },
        [BOARD_DAS1802ST_DA] = {
                .ai_speed       = 3000,
                .qram_len       = 256,
                .ao_ability     = 1,
-               .ao_n_chan      = 4,
                .range_ai       = &range_ai_das1802,
        },
        [BOARD_DAS1802HR] = {
                .ai_speed       = 10000,
                .qram_len       = 256,
                .ao_ability     = 0,
-               .ao_n_chan      = 0,
                .range_ai       = &range_ai_das1802,
        },
        [BOARD_DAS1802HR_DA] = {
                .ai_speed       = 10000,
                .qram_len       = 256,
                .ao_ability     = 1,
-               .ao_n_chan      = 2,
                .range_ai       = &range_ai_das1802,
        },
        [BOARD_DAS1801HC] = {
                .ai_speed       = 3000,
                .qram_len       = 64,
                .ao_ability     = 1,
-               .ao_n_chan      = 2,
                .range_ai       = &range_ai_das1801,
        },
        [BOARD_DAS1802HC] = {
                .ai_speed       = 3000,
                .qram_len       = 64,
                .ao_ability     = 1,
-               .ao_n_chan      = 2,
                .range_ai       = &range_ai_das1802,
        },
        [BOARD_DAS1801AO] = {
                .ai_speed       = 3000,
                .qram_len       = 256,
                .ao_ability     = 2,
-               .ao_n_chan      = 2,
                .range_ai       = &range_ai_das1801,
        },
        [BOARD_DAS1802AO] = {
                .ai_speed       = 3000,
                .qram_len       = 256,
                .ao_ability     = 2,
-               .ao_n_chan      = 2,
                .range_ai       = &range_ai_das1802,
        },
 };
        if (board->ao_ability == 1) {
                s->type         = COMEDI_SUBD_AO;
                s->subdev_flags = SDF_WRITABLE;
-               s->n_chan       = board->ao_n_chan;
+               s->n_chan       = (board->id == DAS1800_ID_ST_DA) ? 4 : 2;
                s->maxdata      = is_16bit ? 0xffff : 0x0fff;
                s->range_table  = &range_bipolar10;
                s->insn_write   = das1800_ao_insn_write;