[NISTC_INTA_ENA_REG]            = { 0x192, 2 },
        [NISTC_INTA2_ENA_REG]           = { 0, 0 }, /* E-Series only */
        [NISTC_INTB_ENA_REG]            = { 0x196, 2 },
-       [Second_IRQ_B_Enable_Register]  = { 0, 0 }, /* E-Series only */
+       [NISTC_INTB2_ENA_REG]           = { 0, 0 }, /* E-Series only */
        [AI_Personal_Register]          = { 0x19a, 2 },
        [AO_Personal_Register]          = { 0x19c, 2 },
        [RTSI_Trig_A_Output_Register]   = { 0x19e, 2 },
                if (enable)
                        val = NISTC_INTA_ENA_G0_GATE;
        } else {
-               reg = Second_IRQ_B_Enable_Register;
+               reg = NISTC_INTB2_ENA_REG;
                if (enable)
-                       val = G1_Gate_Second_Irq_Enable;
+                       val = NISTC_INTB_ENA_G1_GATE;
        }
        ni_stc_writew(dev, val, reg);
 }
 
                                         NISTC_INTA_ENA_AI_SC_TC)
 
 #define NISTC_INTB_ENA_REG             75
+#define NISTC_INTB2_ENA_REG            76
 #define NISTC_INTB_ENA_PASSTHRU1       BIT(11)
 #define NISTC_INTB_ENA_G1_GATE         BIT(10)
 #define NISTC_INTB_ENA_G1_TC           BIT(9)
 #define AO_BC_Save_Registers           18
 #define AO_UC_Save_Registers           20
 
-#define Second_IRQ_B_Enable_Register   76
-enum Second_IRQ_B_Enable_Bits {
-       AO_BC_TC_Second_Irq_Enable = _bit0,
-       AO_START1_Second_Irq_Enable = _bit1,
-       AO_UPDATE_Second_Irq_Enable = _bit2,
-       AO_START_Second_Irq_Enable = _bit3,
-       AO_STOP_Second_Irq_Enable = _bit4,
-       AO_Error_Second_Irq_Enable = _bit5,
-       AO_UC_TC_Second_Irq_Enable = _bit6,
-       AO_UI2_TC_Second_Irq_Enable = _bit7,
-       AO_FIFO_Second_Irq_Enable = _bit8,
-       G1_TC_Second_Irq_Enable = _bit9,
-       G1_Gate_Second_Irq_Enable = _bit10,
-       Pass_Thru_1_Second_Irq_Enable = _bit11
-};
-
 #define AI_Personal_Register           77
 #define AI_SHIFTIN_Pulse_Width                 _bit15
 #define AI_EOC_Polarity                                _bit14