Distribute an on-line data service throughout a corporation using a Data Broadcast Unit.

Electronic Sign Board

 

CEO’s

Async Terminal

 

Async

 

Terminal

in Boardroom

 

RS-232

 

Async Terminal in

Cable

Data Broadcast Unit

Chicago Office

 

On-Line

Data Feed

Modem

Modem

 

Line Driver

Line Driver

Async Terminal

Telco Line

 

 

in Mfg. Plant

 

 

Enhance a security system with parallel data output using the Parallel Data Broadcast/Fallback Unit.

Alarm Panel Parallel Data

Broadcast/

Fallback Unit

Parallel

Cable

Dot-Matrix Printer in

Computer Room

Parallel Line Drivers

Joined with

Twisted-Pair Cable

Dot-Matrix

Printer in

Guard’s Office

Technically Speaking

The Data Broadcast Units and Buffered Data Broadcast Units

regenerate a serial RS-232 async signal and send it to up to eight terminals or printers simultane- ously. The Parallel Data Broad- cast/Fallback Unit sends parallel data to two printers at once, or operates in fallback mode to support a backup printer in case your primary printer fails.

Data Broadcast Units

The DB25 model supports three leads on each port connector: Transmit Data (TXD), Receive Data (RXD), and Signal Ground (SG). Pins 4 and 5 are jumpered internally. Also, pins 6, 8, and 20 are tied internally. The input to the Composite port

is regenerated and simul- taneously sent out on the output lead of each of the eight slave ports, channels 1 through 8.

The RJ-11 model supports pins 2, 3, and 7 only. You will need to order male or female RJ modular adapters for use with this model. See page 4.

Buffered Data Broadcast Units

These units have an internal buffer that is dynamically allocated to the individual ports. “Dynamic allocation” means that a varying amount of buffer is given to each port as it needs it, instead of having a set size of buffer for each port. Additional buffer amounts can be shifted to

ports that are receiving information faster than they can transmit it out to another port(s). Since this allows the buffer to be used most efficiently, system throughput increases. The dynamic allocation works in both directions—when a host is transmitting to the ports and when the ports are transmitting to the host.

Buffered Data Broadcast Units support four slave devices and one master device. They have 32 KB of RAM, with approximately

29.4 KB devoted to buffering. You can expand their channel port capacity and/or RAM with the following items:

A 4-Port Expansion Card that provides 4 additional input ports.

A 32-KB Memory Expansion Card that also provides

25.4 KB more bytes of buffer.

Parallel Data Broadcast/

Fallback Unit

A front-panel switch lets you select from two modes.

Broadcast mode enables

you to get printouts from two locations at the same time.

In fallback mode, if your primary printer fails, your output will automatically switch to an identical secondary printer, so you will be sure to get your printout.

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Black Box DB25 manual Technically Speaking, Data Broadcast Units and Buffered Data Broadcast Units

DB25 specifications

The Black Box DB25 is a versatile and essential connector known primarily for its applications in computer and telecommunications equipment. Characterized by its distinctive D-subminiature design, the DB25 connector has been a staple in the industry since the early days of computing. Its robust construction and reliability have made it a preferred choice for various devices where parallel data transmission is required.

One of the main features of the Black Box DB25 is its ability to handle a maximum of 25 pins, allowing for multiple data channels to be transmitted simultaneously. This configuration supports a variety of communication protocols, making it suitable for connecting printers, serial ports, network interface cards, and multiple peripheral devices. The connector's pin arrangement ensures ease of use while minimizing the chances of misalignment during connection.

The DB25 connector employs a robust locking mechanism that secures the connection, preventing accidental disconnection during operation. This feature is particularly beneficial in environments where devices are frequently connected and disconnected, or in situations that require long cable runs. The durability of the connector is further enhanced by its metal housing, which provides protection against physical damage and electromagnetic interference.

In terms of technology, the Black Box DB25 utilizes a traditional parallel communication scheme for data transfer. Although newer technologies have emerged, the DB25 remains relevant due to its simplicity and reliability. The connector supports data speeds typically up to 1 Mbps, which, while not competing with modern high-speed interfaces, is adequate for many legacy systems and applications.

Another characteristic of the Black Box DB25 is its compatibility with various cable types and assemblies. Users can find both shielded and unshielded versions of the DB25 cables, offering flexibility in terms of electromagnetic compatibility and protective measures against signal loss. The availability of male and female connectors further enhances its adaptability to various hardware configurations.

In conclusion, the Black Box DB25 connector is a reliable and durable solution for parallel data transmission needs. With its robust design, versatile applications, and compatibility with legacy systems, it continues to be a valuable asset for professionals in computing and telecommunications sectors, even amidst rapid technological advancements.