A plain text (no tables) version of this information is also available.

Original IBM PC Connector Pinout vs. TI Professional Connector Pinout:

Notes TI Signal name IBM Signal Name Pin    Pin IBM Signal Name TI Signal name Notes
[1] GroundGroundB1   A1-I/O CH CKNMI [1]
[1] RESET RESET DRV B2   A2 SD7 Data 7 [1]
[1] +5 V dc +5 V dc B3   A3 SD6 Data 6 [1]
[2] IR0 (interrupt 0) IRQ 9 B4   A4 SD5 Data 5 [1]
[3] no connection (bused) -5 V dc B5   A5 SD4 Data 4 [1]
[4] no connection (bused) DRQ2 B6   A6 SD3 Data 3 [1]
[1] -12 V dc -12 V dc B7   A7 SD2 Data 2 [1]
[5] DMA (CPU enable) -0WS B8   A8 SD1 Data 1 [1]
[1] +12 V dc +12 V dc B9   A9 SD0 Data 0 [1]
[1] Ground Ground B10   A10 I/O CH RDY WAIT [1]
[1] AMWC (memory write) -SMEMW B11   A11 AEN Logic ground [7]
[1] MRDC (memory read) -SMEMR B12   A12 SA19 Address 19 (MSB) [1]
[1] AIOWC (I/O write) -IOW B13   A13 SA18 Address 18 [1]
[1] IORC (I/O read) -IOR B14   A14 SA17 Address 17 [1]
[4] no connection (bused) -DACK3 B15   A15 SA16 Address 16 [1]
[4] no connection (bused) DRQ3 B16   A16 SA15 Address 15 [1]
[4] no connection (bused) -DACK1 B17   A17 SA14 Address 14 [1]
[4] no connection (bused) DRQ1 B18   A18 SA13 Address 13 [1]
[4] no connection (bused) -REFRESH B19   A19 SA12 Address 12 [1]
[6] PCLK (5-MHz clock) CLK B20   A20 SA11 Address 11 [1]
[2] IR6 (interrupt 6) IRQ7 B21   A21 SA10 Address 10 [1]
[2] IR5 (interrupt 5) IRQ6 B22   A22 SA9 Address 9 [1]
[2] IR4 (interrupt 4) IRQ5 B23   A23 SA8 Address 8 [1]
[2] IR2 (interrupt 2) IRQ4 B24   A24 SA7 Address 7 [1]
[2] IR1 (interrupt 1) IRQ3 B25   A25 SA6 Address 6 [1]
[4] no connection (bused) -DACK2 B26   A26 SA5 Address 5 [1]
[5] RFSH (refreshing) TC B27   A27 SA4 Address 4 [1]
[1] ALE (address latch) BALE B28   A28 SA3 Address 3 [1]
[1] +5 V dc +5 V dc B29   A29 SA2 Address 2 [1]
[6] OSC (15-MHz clock) OSC B30   A30 SA1 Address 1 [1]
[1] Ground Ground B31   A31 SA0 Address 0 (LSB) [1]


[1] All these pins have the same function with both the IBM and TI busses although the terminology may differ ("AIOWC" vs. "-IOW" where IBM omits the "A" to indicate an advanced signal, one sent ahead of time to give the circuits time to prepare to carry out the operation and uses a preceding "-" to indicate an active low signal where TI uses a trailing "C" to indicate a "Complemented" (active low) signal or the completely different names of "NMI" and "-I/O CH CK" for the same function).

[2] Both busses use these for interrupts and they are identical as far as hardware is concerned. Only the software need differ because different interrupts are activated and different interrupt vectors are used. On the TI, these are used:

      Pin    Hardware interrupt   Interrupt vector number
      B4            IR0               INT 40h
      B21           IR6               INT 46h (disk controller)
      B22           IR5               INT 45h
      B23           IR4               INT 44h
      B24           IR2               INT 42h (communications)
      B25           IR1               INT 41h

[3] No -5V dc is available on the TI. You *could* plug in a card that took the -12V dc from pin B7 and converted it to -5V output on pin B5 to be used by other cards taking the -5 V dc from that pin. (The "bused" means that there is no connection between the TI PC and that pin on the bus but all of the same-numbered "bused" pins on the card connectors are tied together.)

[4] (See also Note [3]) The signals on the IBM PC on these lines are all associated with DMA or refresh. The TI does not use DMA and the refresh method differs on the TI so any IBM card that uses these features will be unusable on the TI.

[5] The signals on these pins differ on the IBM and on the TI but I don't know what conditions are necessary for either of the signals to be invoked or used and have seen no ill effects plugging in an IBM-compatable video card and accessing its static memory.

[6] These carry comparable clock signals on the TI PC and the IBM PC. The frequencies of the clocks differ, however, and anything that is timing-critical should not rely on the clocks being the same.

[7] Forced low on the TI which would disable any DMA on IBM cards.

More information on the IBM PC bus can be found at:

More information on the TI Professional bus can be found at ..., um, well, I can't find anyplace unless you can find a copy of the December, 1983 issue of Byte magazine.