Serial communication still has a role. Used by a lot of older instrumentation, it's effective over distances far longer than USB can handle. But it's slow, and modern computers and laptops often lack a serial port. What they offer instead are multiple USB inputs. Converting serial signals to USB solves several problems.
A serial-to-USB converter performs this function. Without impacting speed or data integrity, it transforms signals in RS-232/422/485 format into USB, or the other way round. Westward Sales carries industrial-grade converters to interface one or more serial data streams with a single USB port on a PC or laptop.
Serial communication is found in equipment used in many different sectors. Access control systems, Intelligent Transportation, data acquisition, process control and automation equipment often employ either an RS-232, RS-422 or RS-485 port. The effective range of RS-232 is 50' (15.2m). RS-422 and RS-485 work over distances up to 4,000' (1,200m). In contrast, the limit for USB 2.0 is 16’ 5” (10m) while for USB 3.0 it’s only 10' (3m).
RS-232 can handle speeds up to 115.2 kbps (and theoretically higher), but it is usually configured as 9.6k or a baud rate of 9,600. RS-422 and RS-485 will go to 10 Mbps. Compare that with USB 2.0's limit of 480 Mbps (USB 3.0 has an even higher throughput of 5Gbps), and one advantage of USB becomes clear. This is why multiple serial connections can go into a single USB port.
The least complicated consists of a cable with a block incorporating a DB9 connector and conversion electronics at one end and a male USB type-A connector at the other. The inexpensive UTS-1110A is an example. An LED indicator signals when the converter is active. Taking power from the USB interface, these are ideal for use with a laptop. Software is provided for configuration at the PC. Both Windows and Linux operating systems are supported.
Permanent installations should use more rugged hardware like the Antaira Technologies’ UTS-402CK industrial 2-Port RS-232 to USB 2.0 converter. Enclosed in a metal case, it accepts two RS-232 connections and outputs data over a USB 2.0 port. For security, it incorporates screw locking for the cable. Surge and isolation protection are built-in. Westward Sales carries converters manufactured by Antaira that handle up to 16 serial inputs (the UTS-416AK) and come with a 5 year warranty.
Serial devices remain commonplace in many industries, but PC connectivity is a growing problem. With a serial-to-USB converter, legacy hardware can remain in place without the range constraints imposed by USB. Contact a Westward Sales product specialist for further information.