Active Oldest Votes 14 +150 Capacitance in the cable begins to affect serial communications, typically many manufacturers/devices set a limit of approximatly 15m or 50ft on cable lengths for anything up to 9600 baud, and about 4m for 38.4k. I've been cross referencing various training books and the serial cable seems to be 25ft or 50ft depending on which one you read The parallel cable seems to be either 6ft, or 10ft, or 16ft depending on which book you read. I'd hate to get the question wrong in the exam due to incorrect information in. Looks like I found my answer. Official specs for 19200baud serial is only 50 feet, Lower that rate to 9600 and you can get an absolute max of about 500 feet! Of course, for that distance I'll need super-high quality cable - something most of my vendors don't seem to be offering.
Serial Cable Maximum Length Calculator
A serial cable is a cable used to transfer information between two devices using a serial communication protocol. The form of connectors depends on the particular serial port used. A cable wired for connecting two DTEs directly is known as a null modem cable.
Maximum cable lengths[edit]
The maximum working length of a cable varies depending on the characteristics of the transmitters and receivers, the baud rate on the cable, and the capacitance and electrical impedance of the cable. The RS-232 standard states that a compliant port must provide defined signal characteristics for a capacitive load of 2500 pF. This does not correspond to a fixed length of cable since varying cables have different characteristics. Empirically tested combinations of bit rate, serial ports, cable type, and lengths may provide reliable communications, but generally RS-232-compatible ports are intended to be connected by, at the most, a few tens of metres of cable. Other serial communications standards are better adapted to drive hundreds or thousands of metres of cable.
See also[edit]
Serial Cable Maximum Length
| Wikibooks has a book on the topic of: Serial Programming:RS-232 Connections |
- LapLink cable (can be seen as a parallel equivalent to a serial null modem cable)
- Rollover cable (also known as a 'Yost' cable.)
A serial cable is a cable used to transfer information between two devices using a serial communication protocol. The form of connectors depends on the particular serial port used. A cable wired for connecting two DTEs directly is known as a null modem cable.
Maximum cable lengths[edit]
The maximum working length of a cable varies depending on the characteristics of the transmitters and receivers, the baud rate on the cable, and the capacitance and electrical impedance of the cable. The RS-232 standard states that a compliant port must provide defined signal characteristics for a capacitive load of 2500 pF. This does not correspond to a fixed length of cable since varying cables have different characteristics. Empirically tested combinations of bit rate, serial ports, cable type, and lengths may provide reliable communications, but generally RS-232-compatible ports are intended to be connected by, at the most, a few tens of metres of cable. Other serial communications standards are better adapted to drive hundreds or thousands of metres of cable.
See also[edit]
Serial Cable Maximum Length
| Wikibooks has a book on the topic of: Serial Programming:RS-232 Connections |
- LapLink cable (can be seen as a parallel equivalent to a serial null modem cable)
- Rollover cable (also known as a 'Yost' cable.)
References[edit]
9 Pin Serial Cable Max Length
