- (Communications Port ) PC . [1] RS-232C. - (UART), i8250/16450/16550. - 8 8- 3F8h (COM1), 2F8h (COM2), 3E8h (COM3), 2E8h (COM4). IRQ4 ( COM1 COM3) IRQ3 ( COM2 COM4). , , RS-232C. - - (male ) DB25P DB9P, (. . 2.1). ˻ . . 115 200 /.
COM1-COM4 ( AT ) BIOS. BIOS Int 14h , ( ) . Int 14h 110-9600 / (, ). , - i8250/16450/16550.
(, ) , . : , , . - , . - .
( PCI- 486) -. (IrDA). ISA -, LPT-, (FDC+IDE). , -. , 4, 8, 12 16 . , ( ), . BIOS .
|
|
- - , . FIFO- DMA, , .
RS-232C
RS-232C , ( , ; DTE Data Terminal Equipment), (; DCE Data Communication Equipment). , , . . . . 2.1; , - (. 2.2).
. 2.1. RS-232C
. 2.2. RS-232C -
, , . , - . RS-232C V.24/V.28 2, .
RS-232C ( , RS-422). . -12 -3 . ON (), MARK. +3 +12 . OFF (), SPACE. -3 +3 , : (. 2.3). -12 -5 +5 +12 . (SG) 2 , .
, .
. ( ) .
|
|
RS-232C .
( -) DB-25P DB-9P. , ( 25- ).
() DB-25S DB-9S.
. 2.3. RS-232C
, , . 9 25- (. 2.4).
. 2.4.
, () - (Zero-modem, Z-modem), , , . 2.5.
. 2.5. - : ,
- 100 % , , . , .
. 2.1 - ( ). DB-25S EIA/TIA-232-E, DB-9S EIA/TIA-574. () , (-) .
2.1. RS-232C
| PC | ||||||||
- | RS-232 | V.24 2 | DB-25 | DB-9 | 11 | 22 | 33 | 44 | I/O |
PG | AA | 101 | 1 | 5 | (10) | (10) | (10) | 1 | - |
SG | AB | 102 | 7 | 5 | 5 | 9 | 1 | 13 | - |
TD | BA | 103 | 2 | 3 | 3 | 5 | 3 | 3 | O |
RD | BB | 104 | 3 | 2 | 2 | 3 | 4 | 5 | I |
RTS | CA | 105 | 4 | 7 | 7 | 4 | 8 | 7 | O |
CTS | CB | 106 | 5 | 8 | 8 | 6 | 7 | 9 | I |
DSR | CC | 107 | 6 | 6 | 6 | 2 | 9 | 11 | I |
DTR | CD | 108/2 | 20 | 4 | 4 | 7 | 2 | 14 | O |
DCD | CF | 109 | 8 | 1 | 1 | 1 | 5 | 15 | I |
RI | 125 | 22 | 9 | 9 | 8 | 6 | 18 | I |
1 8- .
2 16- .
3 .
4 25- .
RS-232C, , - PC. , - ( RS-232 V.24). , () ( -3 ) , ( +3 ). . 2.2. - . 2.6.
2.2. RS-232C
PG | Protected Ground , |
SG | Signal Ground () , |
TD | Transmit Data |
RD | Receive Data |
RTS | Request To Send : . |
CIS | Clear To Send . . |
DSR | Data Set Ready ( ) |
DTR | Data Terminal Ready . |
DCD | Data Carrier Detected |
RI | Ring Indicator (). |
|
|
. 2.6.
1. DTR .
2. DSR .
3. RTS .
4. CTS .
5. CTS (, ) .
6. CTS ( ).
7. RTS ( ), . .
8. RTS CTS.
9. RTS .
10. .
11. .
12. .
13. DTR, ( ).
14. DSR .
DTR-DSR RTS-CTS - .