USB to RS232 / RS485 / RS422 / TTL Converters

2. Why do terminal blocks make installation simple?

For USB to RS485, RS422 or TTL adapters an included terminal block is very important. Some converters on the market do not come with them. A terminal block is a screw down wire adapter that attaches to the DB9 serial adapter. It simplifies cable installation to attached cables such as CAT5 or CAT5e without the need to make a custom cable or adapter. Without the terminal block a custom cable needs to be made and that can be time consuming and expensive. Even if you are using the DB9 in your present installation it makes sense to have one for future applications. All of our high quality USB to RS485/RS422/TTL converters include terminal blocks at no extra charge.

3. How and why is 120 OHM termination used?

Our USB to RS485 or USB to RS485/RS422 adapters come with terminal blocks with 120 Ohm termination selectable via a jumper on the terminal block. 120 Ohm is an advanced feature that impedance matches the cable system. In some cases where the cable runs are greater then 600 feet or baud rate is over 19.2K there could be noise or reflections on the RS485/RS422 lines resulting in unreliable communication. In most cases, 120 ohm termination is not required but without the easy to use selectable 120 Ohm termination resistor on the terminal block, the resistor may have to be soldered on the ends of the cable runs making it an undesirable situation.

4. Why do our products feature auto-turnaround?

USB to RS485, RS422 or TTL converters come with the built-in autosensing auto-turnaround. The start bit of the data is automatically sensed thus changing the direction of the data flow avoiding the possibility of data collisions. This is handled automatically by the signal processor and eliminates the requirement of using software drivers or flow control. This is very important especially for RS485 since it is half duplex meaning it transfers data only in one direction at a time.

5. Why our products come with ESD and surge protection?

Electrostatic or ESD static protection and surge suppression protection is a standard feature on all our products. Our products come with 15KV ESD protection and 600W/sec burst surge protection. These features was tested in the factory lab and during CE and FCC testing by an independent testing facility.

6. How external LEDs help in debugging?

USB to Serial Adapters with PWR, TX and RX LEDs make is easy to see if power is on and whether data is being transferred. Although this feature is not necessary it makes it useful for debugging purposes and is quite helpful.

7. Do I need commercial, industrial or miltary grade?

Commercial, industrial and military grades are basically operating temperature range classifications. Commercial grade has a typical temperature range of 32ºF to 158ºF (0ºC to 70ºC). For most indoor (home, lab or server room) applications this is sufficient and extended temperature ranges are not required because these locations are temperature controlled. Industrial and military classified devices have extended temperature ranges. Industrial grade typically has a temperature range from -40ºF to 185ºF (-40ºC to 85ºC) while military grade typically has temperature range from -67ºF to 257ºF (55ºC to -125ºC). Commercial grade verses industrial grade has nothing to do with reliability engineering, vibration or shock susceptibility and other environmental factors. Customers should be leery of misleading claims that because products meet the industrial temperature range they are reliability engineered, rugged, shock resistant, vibration resistant and environmentally superior. Many semiconductor companies use the same die for the different classifications and grade them according to their operating temperature tests. Please with see the associated Wikipedia article for more information on temperature range classifications.

8. Are rugged converters really necessary?

Ruggedized converters are converters that are not susceptible to vibration and shock and must be specially reliability tested for that. Ruggedized converters are not really needed in most applications unless you are in an environment susceptible to vibration and other adverse environmental factors such as off roading, on a boat or a plane. All Serialcomm USB adapters are vibration, free fall, and shock tested as part of our standard product testing. Some of our converters come with two terminal blocks one rugged and the other with 120 ohm selectable jumper. Both terminal blocks are of the highest quality and can be used in any application but SerialComm believes a terminal block with a friction held jumper cannot be ruggedized or vibration resistant and that is why give the customer the option of a terminal block without any friction held jumpers. Any claims that terminal blocks with exposed jumpers are ruggedized and vibration resistant are deceiving.

9. Are regular or opto-isolated converters needed?

Serialcomm offer both regular and opto-isolated converters. Opto-isolated converters are usually used outdoors or in applications with noise or ground loop problems. There is no electrical signal path between one connector and the other and use optical LEDs to transfer data. This will protect your devices from voltage spikes and lighting and make the converter less susceptible to noise and ground loops. Opto-isolation is not surge suppression and the difference is a damaging voltage surge might destroy the converter and not the device it is protecting thus protecting your expensive device or computer.

10. How is quality engineering & standardized product testing important?

Quality engineering and standardized product testing is an important factor to ensure reliability in our products. Serialcomm products have an industry proven high reliability rate over 99% and are CE, FCC and RoHS certified. And because of this, we offer a 5 year replacement warranty on our products. As part of our commitment to providing the highest quality and reliable products some of the tests performed on our products include temperature, vibration, free fall, shock, EMI emissions and EMI radiation susceptibility and other environmental tests.

11. Why is reliable brand important?

Serialcomm is an industry proven reliable brand you can trust. Serialcomm has sold to many of the high tech leaders both in the U.S. and abroad. We back all our products with a 30 day money back guarantee and 5 year replacement warranty and we do not charge a restocking fee if product is returned. Serialcomm products are designed with proven engineering techniques with an established quality assurance program. Some companies sell converters from a multitude of Chinese manufactures with all different levels of quality and they do not now how they are designed or tested. Serialcomm offer the highest quality products at wholesale prices.

12. Importance of 12/7 telephone and live chat support?

We offer 24/7 telephone and live chat support as well as email support. Some companies only offer email support. Serialcomm is dedicated to its products and customer support. If you need technical help or have a question you want to be assured you can talk to an engineer/customer/sales support at your schedule without having to wait for an email response that can take days.

13. Why we do not charge restocking fees?

A restocking fee is a handling charge that some companies charge when product is returned. Customers should be careful of companies that charge as high as a 20% restocking fee with the only customer disclosure in their Terms and Conditions statement. At Serialcomm we give you 30 days to decide whether you want to return the product at a full refund without any penalties or additional fees.

14. How free shipping and guaranteed express important?

We offer free shipping on all our products. This is a major savings for our customers. We do not offer a very low price and then add extra charges on the shipping to make up for the low price. We also offer optional expedited services by FEDEX, UPS and DHL. We offer FEDEX express services up to 7:30 PM EST or 4:30 PST which is the most flexible schedule on the market. If you decide to use your courier account we do not add any additional handling charges. We pride ourselves in our track record of getting packages to FEDEX on time.