D or P – is the letter “D” or “P” (if P, the data will not be echoed locally),

data – is the user data.

An example of a Call Request to called address 1000000000 with the Reverse Charging facility plus user data “ abcde” is: R-1000000000Dabcde

An Abbreviated Address can be substituted for the complete called address if no facilities are included. Also, X.28 convention demands that when sending a Call Request packet using an abbreviated address, you precede the address with a period. If you want to add user data to the packet, you must separate it from the abbreviated address with an asterisk. The format is: .address*data

If the Call Request is successful, the async PAD will receive a Call Accept packet from the device at the other end of the call. Connection is now established, and the terminal will display COM. If the Call Request fails, the terminal will display a diag- nostic message explaining why. The various messages are some of the PAD service signals described later in this appendix.

To send data once you are in Data Transfer mode, simply enter the data. To clear a call, enter Command mode and type clr [Enter] . The async terminal will display: CLR conf.

Async PAD Service Signals

Transmission of PAD service signals is determined by async PAD profile parameter 6.

*(Asterisk) – is normally the PAD prompt character.

“nnnnn” COM – means that a vitual circuit has been established with a subscriber whose ID is “nnnnn.”

ALREADY CONNECTED – indicates there is already a VC set up, so another call cannot be made until the current call is cleared.

AUTOCALL INITIATED BY SUBSCRIBER “nnnmm” – is self-explanatory.

AUTOCALL RETRIES EXHAUSTED-RETURN TO COMMAND STATE – means that the

autocall retry timer has expired.

CALL CLEARED – indicates that the call is being cleared.

CALL TIMED OUT – is displayed when the network does not respond to a virtual circuit call setup request within a certain time.

CLR (cause) (cause code) (diagnostic code) – is displayed when the call is cleared.

Some common causes and codes are listed in Appendix B.

CLR CONF – confirms the clearing of a call.

DISCONNECT TIMER EXPIRED – indicates that the inactivity timer on the port has expired.

Async Terminal Operations

A-3

Page 382 Page 384
Page 383
Image 383
Cabletron Systems 1800 manual Async PAD Service Signals
Page 382 Page 384

1800 specifications

Cabletron Systems, a leading player in network management and telecommunications solutions during the late 20th century, introduced several innovative products that played a crucial role in shaping enterprise networking. Among these were the Cabletron FRX6000, FRX4000, and the FRX1800, which delivered advanced features aimed at enhancing network performance, security, and scalability.

The Cabletron FRX6000 was designed as a robust multi-layer switch, ideal for large-scale enterprise environments. It supported extensive routing capabilities, allowing organizations to manage traffic efficiently even under heavy loads. The FRX6000 boasted high throughput rates and low latency, making it suitable for demanding applications. With support for various network protocols, including IP, IPX, and AppleTalk, its adaptability made it a versatile choice for diverse networking needs. Moreover, security features like VLAN support and Access Control Lists (ACLs) provided enhanced protection against potential threats.

Moving to the FRX4000, this model offered a balance between performance and cost-effectiveness. The FRX4000 maintained many of the essential features of its larger counterpart while catering to medium-sized enterprises. It provided Layer 3 routing and could handle multiple simultaneous connections, ensuring seamless communication across departments. The modular design allowed for easy upgrades, enabling businesses to expand their network infrastructure without significant overhauls. This made the FRX4000 an attractive option for organizations looking to optimize their network investments.

Lastly, the FRX1800, designed for small to medium businesses, focused on simplicity and ease of use while still incorporating powerful network management capabilities. Its user-friendly interface made it accessible for organizations lacking extensive IT resources. The FRX1800 provided essential functionalities such as Integrated Layer 2 switching and routing, network monitoring, and basic security features, ensuring that even smaller companies could maintain efficient, reliable networking without overwhelming complexity.

All three models utilized advanced technologies, including a high bandwidth backbone and state-of-the-art switching architecture, to enable fast and reliable data transfer. They also supported Quality of Service (QoS) mechanisms, allowing businesses to prioritize critical applications and ensure consistent performance across the network.

In summary, the Cabletron FRX6000, FRX4000, and FRX1800 were pivotal in enhancing network capabilities, providing organizations with scalable, secure, and high-performance options tailored to their specific needs.
Top Page Image Contents