The table provides a list comparing the different types of data buses. Both
serial and parallel buses are detailed. Color-coding of the table groups buses
with similar structures or function.
The first column gives the "common" name of the bus.
Depending on the bus type, either data rate or throughput is given in the second
column. Clocked buses are shown with the clock rate [as data rate], while buses
that allow hand shaking are listed with through-put, bits/bytes per second as the
data rate ['b'= bits, 'B'= Bytes]. Many of the serial buses are in Baud-rate. The data rate numbers
will normally be best case; requiring shortest cable distance, no wait states,
optimal communication between devices and so on.
The next column called 'Type' is really the width of the bus in bits. Fiber,
Balanced, Unbalanced, and Differential are all types of serial buses. However
all the new "serial" buses may grow in width by providing [sending/receiving]
multiple serial paths.
A short description of the bus is provided, followed by the bus topology column.
Than the nominal bus voltage level is listed
The two columns to the far right indicate the physical nature of the bus; back
plane, cable, fiber... The acronyms UTP [Un-shielded Twisted Pair], and STP
[Shielded Twisted Pair] are indicated for some of the serial buses. Some of the
parallel buses just use this column for more detail.
You can either go to a particular bus page by using the Bus Specifications link, or by following the link provided for each bus type below. A link is not always given for each bus version, only because they would all point to the same page.
| Cable and Back Plane Bus Standards |
| Bus |
Data Rate |
Type |
Description |
Topology |
Voltage |
Coax |
Twisted Pair |
| RS-170 |
Video |
Unbalanced |
Video, 75 Ohm |
Point-to-Point |
~ 1V |
75 Ohm |
------- |
| RS-232 |
19.2 Kbps |
Unbalanced |
20 meters, Single Ended |
Point-to-Point |
~ 5V |
15 or 25 pin cable |
| RS-422 |
100 Kbps |
Balanced |
1200 meters, Differential, 100 Ohms |
Multi-Receivers |
+/-7V |
------ |
See RS449 / 530 |
| RS-423 |
100 Kbps |
Hybrid |
200 meters, Unbal Tx Bal Rx |
Multi-Receivers |
+3.6V |
------ |
See RS449 / 530 |
| RS-485 |
100 Kbps |
Balanced |
1200 meters, Differential |
Multi-Point |
+5V |
------ |
STP or UTP |
| RS-562 |
64 Kbps |
Unbalanced |
Mates to RS-232 (low voltage) |
Point-to-Point |
+/- 3.7v |
TBD |
| EIA-568 |
100MHz |
Balanced |
90 meters |
Multi-Point |
------ |
------ |
UTP CAT5 |
| RS-612 |
52 Mbps |
Balanced |
Unidirectional |
Point-to-Point |
ECL |
Shielded cable 25 Twisted pair |
| EIA-644 |
655 Mbps |
Balanced |
10 meters, LVDS Elec. Spec only |
All types |
0.0~2.4V |
Back Plane or Cable |
| RS-694 |
512 kbps |
Unbalanced |
Mates with RS-232 |
Point-to-Point |
RS232 |
------ |
------ |
| MIL-STD-1553 |
1.0 Mbps |
Balanced |
Redundant, half-duplex |
Multi-Point |
0 to 20V |
75 Ohm Twinax |
| CAN bus |
1 Mbps |
Balanced |
High Noise Environment |
Multi-Point |
+16V max |
------ |
STP or UTP |
| AccessBus |
100 Kbps |
Unbalanced |
Similar to I2C, 10 meter |
Multi-Point |
~ 5V |
4 wire,Data/Clk/V/GND |
| I2C Bus |
3.4 Mbps |
Unbalanced |
2 Wire, 1 Data, 1 Clk-Access Bus |
Multi-Point |
~ TTL |
PWB |
| SMBus |
100 KHz |
Unbalanced |
2 Wire, based on I2C/Access Bus |
Multi-Point |
TTL |
Undefined |
| 10Base2 |
10 Mbps |
Unbalanced |
183 meters, IEEE-802 Thin Net |
Multi-Point |
ECL |
50 Ohm |
------ |
| 10Base5 |
10 Mbps |
Unbalanced |
500 meters, IEEE-802 ThickNet |
Multi-Point |
ECL |
50 Ohm |
------ |
| 10Base-T |
10 Mbps |
Balanced |
100 meters, Category 3 cable |
Multi-Point |
ECL |
------ |
STP or UTP |
| 10Base-F |
10 Mbps |
Fiber |
2000 meters |
Point-to-Point |
--- |
Fiber |
| 100Base-T |
100 Mbps |
Balanced |
100 meters, Category 5 cable |
Multi-Point |
+/- 1.0v |
------ |
STP or UTP |
| 100Base-F |
100 Mbps |
Fiber |
2000 meters |
Point-to-Point |
--- |
Fiber |
| Gigabit Ethernet |
1000 Mbps |
Fiber or 1000Base-T |
Uses Fibre Channel or EIA568 CAT5 |
Point-to-Point |
+/- 1.0v |
Fiber or EIA568 STP |
| ATM |
155 Mbps |
N/A |
Not the Physical Layer |
Point-to-Point |
N/A |
Fiber or STP |
| SONET |
9953.28Mbps |
Fiber |
STS-3 is 155.52Mbps |
Point-to-Point |
Optical |
Fiber |
| Fibre Channel |
1 Gbps |
Differential |
SCSI like, Fiber, Coax, or TP |
Point-to-Point |
ECL |
Yes |
Yes |
| FDDI |
100 Mbps |
Fiber |
CDDI uses copper |
Token Ring |
ECL/PECL |
Fiber or Copper |
| HIPPI |
100 Mbps |
Fiber |
Fiber or Copper |
Point-to-Point |
Diff ECL |
Fiber or Copper |
| HSSI |
52 Mbps |
Balanced |
SCSI II like |
Point-to-Point |
Diff ECL |
------ |
STP |
| RapidIO |
10 Gbps |
Balanced |
Differential LVDS |
Star / Mesh |
LVDS |
Back Plane or Cable |
| InfiniBand |
2.5 Gbps |
Balanced |
Differential LVDS Pairs |
Point-to-Point |
LVDS |
Copper or Fiber |
| HyperTransport |
800Mbps/bit pair |
Balanced |
2/4/8/16/32 bits |
Daisy-Chained |
LVDS |
PWB |
| FireWire, 1394a |
400 Mbps |
Differential |
USB like, Back Plane or cable |
Point-to-Point |
0.6~0.8V |
2 pairs of STP & 2 Power |
| FireWire, 1394b |
800 Mbps |
Differential |
"...." 1394b |
Point-to-Point |
0.6~0.8V |
2 pairs of STP & 2 Power |
| USB |
12 Mbps |
Differential |
USB 1.1 |
Star Topology |
0.3~3.6V |
------ |
STP |
| USB |
480 Mbps |
Differential |
USB 2.0 |
Star Topology |
0.3~3.6V |
------ |
STP |
| IEEE-488 |
1 Mbps |
8 Bits |
Equipment Control |
Chained |
TTL |
24 Pin cable |
| HS-488 |
8 Mbps |
8 Bits |
Equipment Control, ignores NDAC |
Chained |
TTL |
24 Pin cable |
| ATA-1 |
8.3Mbps |
8 Bits |
IDE; Hard / Floppy / CD Drive |
Chained |
Obsolete |
40 pin ribbon cable |
| ATA-2 |
16 Mbps |
8 Bits |
IDE; Hard / Floppy / CD Drive |
Chained |
Obsolete |
40 pin ribbon cable |
| ATA-3 |
16 Mbps |
16 Bits |
EIDE; Hard / Floppy / CD Drive |
Chained |
TTL |
40 pin ribbon cable |
| ATA-4 |
33 Mbps |
16 Bits |
"......." Ultra ATA/33,Added CRC |
Chained |
TTL |
80 pin ribbon/40 connect |
| ATA-5 |
66 Mbps |
16 Bits |
"......." Ultra ATA/66,Added CRC |
Chained |
TTL |
80 pin ribbon/40 connect |
| ATA-6 |
100 Mbps |
16 Bits |
"......." Ultra ATA/100,Added CRC |
Chained |
TTL |
80 pin ribbon/40 connect |
| ATA-7 |
133 Mbps |
16 Bits |
"......." Ultra ATA/133,Added CRC |
Chained |
TTL |
80 pin ribbon/40 connect |
| Serial ATA |
150MBps |
Differential |
2 differential pairs [Tx/Rx] |
Point-to-Point |
LVDS |
4 conductor cable |
| SCSI-1 |
5 MBps |
8 Bits |
Peripheral Control, 7 devices |
Chained |
Obsolete |
50 pin connector |
| SCSI-2 |
40 MBps |
8 / 16 /32 Bit |
Peripheral Control, 11 devices |
Chained |
TTL |
50 or 68 pin connector |
| SCSI-3 |
40 MBps |
8 / 16 Bit |
Peripheral Control, 16 devices |
Chained |
TTL |
50 or 68 pin connector |
| Ultra 160 SCSI |
160 MBps |
32 Bit |
Peripheral Control, 4 devices |
Chained |
TBD |
TBD |
| Ultra 320 SCSI |
320 MBps |
32 Bit |
Peripheral Control, 4 devices |
Chained |
TBD |
TBD |
| Ultra 640 SCSI |
640 MBps |
32 Bit |
Peripheral Control, 4 devices |
Chained |
TBD |
TBD |
| PC-XT |
4.7MHz |
8 Bits |
Personal Computer Bus |
Card edge |
TTL |
Obsolete |
| PC-AT (ISA) |
8MHz |
16 Bits |
Personal Computer Bus |
Card edge |
TTL |
Still used on PC104 |
| EISA |
8MHz |
32 Bit |
PC local bus |
Card edge |
TTL |
Obsolete |
| Micro Channel |
10MHz |
32 Bits |
Personal Computer Bus |
Card edge |
TTL |
Obsolete |
| VESA (VLB) |
33MHz |
32/64 Bit |
PC local bus |
Card edge |
TTL |
Obsolete |
| PISA |
Combo |
Combo |
ISA-PCI Combo @ISA Format |
Card edge |
TTL |
Industrial Computers |
| PCI |
33/66MHz |
32/64 Bits |
Chip-to-Chip, Multidrop PC Local Bus |
Card edge |
TTL |
Computers |
| PCI-X |
533MHz |
32/64 Bits |
Chip-to-Chip, Multidrop 4.3GBps |
Card edge |
CMOS |
Computers |
| PC Card |
8MHz |
16 Bit |
ISA in a PCMCIA form factor |
Connector-ized |
TTL |
Computers |
| CardBus |
33MHz |
32 Bit |
PCI in a PCMCIA form factor |
Connector-ized |
PCI |
Computers |
| AGP |
66MHz |
8/16/32 Bit |
PC local bus similar to PCI |
Point-to-Point |
TTL |
Accelerated Graphic Port |
| AGP 2x |
133MHz |
8/16/32 Bit |
"....." 533MB/s |
Point-to-Point |
TTL |
Accelerated Graphic Port |
| AGP 4x |
266MHz |
8/16/32 Bit |
"....." 1066MB/s |
Point-to-Point |
TTL |
Accelerated Graphic Port |
| AGP 8x |
533MHz |
8/16/32 Bit |
"....." 2.1GB/s |
Point-to-Point |
TTL |
Accelerated Graphic Port |
| PCI Express |
2.5Gb/ps |
up to 32 Bits |
Serial PCI, differential pairs |
Point-to-Point |
TBD |
TBD |
| AMR/CNR |
TBD |
TBD |
Audio/Modem-Communication Network Riser |
TBD |
TBD |
Card Edge |
| PC104 |
8MHz |
8/16 Bit |
ISA-AT Stacked PC Cards |
Back Plane |
TTL |
Embedded Computers |
| PC104-Plus |
8MHz and 33MHz |
8/16/32 Bit |
PCI - PC104 Combo |
Back Plane |
TTL |
Embedded Computers |
| Compact-PCI |
266/512Mbps |
32/64 Bit |
33MHz/66MHz, VME format |
Back Plane |
CMOS |
110 pin 2mm connector |
| PXI |
33MHz |
32/64 Bit |
cPCI for Instrumentation 3U/6U |
Back Plane |
TTL |
Industrial Computers |
| AdvancedTCA |
TBD |
TBD |
8U card size |
Back Plane |
TBD |
TBD |
| VME |
40 Mbps |
8/16/32 Bit |
Euro card format 3U/6U x160mm |
Back Plane |
TTL |
96 pin P1/P2 |
| VME64 |
80 Mbps |
8/16/32/64 Bit |
3U/6U x160mm, 6U/9U x320mm, |
Back Plane |
TTL |
190 pin P1/P2, 92 pin P0 |
| VME64x |
160 Mbps |
8/16/32/64 Bit |
2eVME; 3U/6U/9U x160mm (x320mm) |
Back Plane |
TTL/ETL |
190 pin P1/P2, 92 pin P0 |
| VME320 |
320 Mbps |
8/16/32/64 Bit |
2eSST; 3U/6U/9U |
Back Plane |
ABTL |
Copy Right-ed |
| VXI |
80 Mbps |
64 Bit |
VME for Instrumentation 3U/6U/9U |
Back Plane |
TTL |
96 pin P1/P2 |
| Mezzanine |
33/64MHz |
8/16/32 Bit |
PMC and PC MIP cards |
Daughter card |
PCI |
Daughter Bus |
| P2CI |
33MHz |
64 Bit |
VME P2 bus with PCI |
Back Plane |
TTL |
VME64x P2 Connector |
| RaceWay |
40MHz |
32 Bit |
VME P2 Crossbar 480Mbps |
P2 rear rows A/C |
TTL |
P2 Daughter card |
| SkyChannel |
320Mbps |
32 Bit |
VME P2 Crossbar add-on |
P2 rear rows |
TTL |
P2 Daughter card |
| FPDP |
160Mbps |
32 Bit |
VME (Front Panel Data Port) |
Point-to-Point |
PECL |
Front Panel Connector |
| AutoBahn |
200Mbps |
Differential |
VME P1 |
Point-to-Point |
PECL |
Serial Bus |
| Futurebus /+ |
100/3200 Mbps |
100/256 Bit |
300mm x 300mm card |
Back Plane |
BTL |
2mm Connectors |
| Std32 Bus |
32 Mbps |
8/16/32 Bit |
Industrial Bus |
Back Plane |
TTL |
Industrial Computers |
| MultiBus II |
80 Mbps |
32 Bit |
3U/6U x 220mm |
Back Plane |
TTL |
DIN 41612 |