Black Box Explains...IRQs, COM Ports, and Windows
Product Data Sheets (pdf)...PC Plus Adapters
Windows® 95 normally requires each serial port to have its own unique Interrupt Request Line (IRQ). However, if you use a third-party communications driver that supports IRQ sharing, you can... more/see it nowshare interrupts. Unfortunately, data throughput will not be as high as with single interrupt port configurations.
With Windows NT®, you can share interrupts across multiple ports as long as the serial ports have an Interrupt Status Port (ISP) built into the card.
The Interrupt Service Routine, a software routine that services interrupts and requests processor time, reads the ISP and is immmediately directed to the port that has an interrupt pending. Compared to the polling method used if the serial ports don’t have an ISP, this feature can determine which port generated the interrupt up to four times more efficiently—and it almost eliminates the risk of lost data. Windows NT supports the ISP by enabling the user to configure the registry to match the card’s settings. Black Box models IC102C-R3, IC058C, and IC112C-R3 all have ISPs and come with a Windows NT setup utility to simplify installation and configuration.
If your serial port doesn’t have an ISP, the Interrupt Service Routine has to poll each port separately to determine which port generated the interrupt. collapse
Product Data Sheets (pdf)...PQ-7
Product Data Sheets (pdf)...Terminal Eliminator Plus
Industrial Ethernet Surge Protector DIN Rail Specification Sheet
Specification Sheet for the ICD300A
Black Box Explains...Power problems.
Product Data Sheets (pdf)...Parallel Line Drivers
The Threat — A sag is a decline in the voltage level. Also known as “brownouts,” sags are the most common power problem.
The Cause — Sags can be caused... more/see it nowlocally by the start-up demands of electrical devices such as motors, compressors, and elevators. Sags may also happen during periods of high electrical use, such as during a heat wave.
The Effect — Sags are often the cause of “unexplained” computer glitches such as system crashes, frozen keyboards, and data loss. Sags can also reduce the efficiency and lifespan of electrical motors.
The Threat — A blackout is a total loss of power.
The Cause — Blackouts are caused by excessive demand on the power grid, an act of nature such as lightning or an earthquake, or a human accident such as a car hitting a power pole or a backhoe digging in the wrong place.
The Effect — Of course a blackout brings everything to a complete stop. You also lose any unsaved data stored in RAM and may even lose the total contents of your hard drive.
The Threat — A spike, also called an impulse, is an instantaneous, dramatic increase in voltage.
The Cause — A spike is usually caused by a nearby lightning strike but may also occur when power is restored after a blackout.
The Effect — A spike can damage or completely destroy electrical components and also cause data loss.
The Threat — A surge is an increase in voltage lasting at least 1/120 of a second.
The Cause — When high-powered equipment such as an air conditioner is powered off, the excess voltage is dissipated though the power line causing a surge.
The Effect — Surges stress delicate electronic components causing them to wear out before their time.
The Threat — Electrical noise, more technically called electromagnetic interference (EMI) and radio frequency interference (RFI), interrupts the smooth sine wave expected from electrical power.
The Cause — Noise has many causes including nearby lightning, load switching, industrial equipment, and radio transmitters. It may be intermittent or chronic.
The Effect — Noise introduces errors into programs and data files. collapse
4-Port Industrial-Grade USB Hubs User Manual
User Manual for the ICI200A and ICI202A (Version 1)
Black Box Explains...DDS vs. T1.
Product Data Sheets (pdf)...FlexPoint RS-232 to Fiber Converters
DDS (Digital Data Service) is an AT&T® service that transmits data digitally over dedicated leased lines. DDS lines use four wires, and support speeds up to 56 kbps; however, DDS... more/see it nowis actually a 64-kbps circuit with 8 kbps being used for signaling. You can also get 64-kbps (ClearChannel™) service. Since the transmission is digital, no modems are needed. Dedicated digital lines are ideal for point-to-point links in wide-area networks.
T1 is a dedicated transmission line operating at 1.544 Mbps. It’s comprised of 24 DSOs, each supporting speeds of 64 kbps. The user sends data at N x 56 or N x 64 over T1 circuits. T1 operates over twisted-pair cable and is suitable for voice, data, and image transmissions on long-distance networks. collapse