3Com S200 Network Parity Application Response Delay DTR Timeout, ATPAD Application Environment

ATPAD Ports

Network Parity Application

Response Delay

DTR Timeout

The application that the network parity feature has been designed for is as follows. An async device is directly connected to the ATPAD, and a call is made to an X.25 host. The ATPAD port currently strips parity on the incoming async data, so that the data on the X.25 link is always 8 bits, no parity. Normally, the PAD at the remote site would regenerate parity when it transmits the data. In this application, the connection is to an X.25 host, which is expecting the data to be 7 bits, even parity.

This enhancement allows for selection of the parity requirements for data transmission. This configuration is shown in Figure 12.

Async	Network	X.25
PC	Access	8 Bits, No Parity	X.25
7 Bits	Product		Host
Even Parity

Figure 12. ATPAD Application Environment

If it is necessary to slow down the responses sent by an ATPAD port, you can configure Response Time using this CSK: BSYJWMYCCCKK6HE9NKEE. This CSK causes all ATPAD ports on the node to delay sending responses to commands for a period of 1 second.

This feature is designed for this situation. If an automated device that you are using to send commands to an ATPAD port has trouble recognizing the responses when they arrive too quickly, this feature will delay responses. This feature is not recommended when the commands are being issued by a human operator.

Note

The ATPAD does not have type-ahead capability, so commands that are sent before the response to the previous command has been received are ignored.

The standard timeout period for DTR Connection Type is 1.5 seconds. This means that DTR is not recognized as being in the OFF state until it has been OFF for a continuous period of 1.5 seconds. If you need a shorter timeout period, you can configure it using this CSK: DTZEFG4JHTQY2HCFBJ66.

This CSK will change the timeout period for all ports on the node with DTR Connection Type to 100 ms. To guarantee reliable operation in this mode, a minimum OFF time of 150 ms for DTR is recommended.

60 Configuring PAD/ATPAD Ports