3Com Courier Reference

Contents

3Com Courier Reference Manual pdf 124 page image

16-2 C HAPTER 16: D EDICATED/L EASED L INE AND SYNCHRONOUS APPLICATIONSRequirements The information below describes device requirements.Find out what hardware and software you need before proceeding.A Device with aSynchronous SerialPortYou will probably have to purchase and install a synchronous adaptercard. These cards provide: A synchronous serial port Support for one or more synchronous protocols. Additional software functions. For example, the card may tell themainframe what type of computer or terminal you are using. The cardmay also tell the mainframe what resources you want to use.A Serial Cable Obtain a shielded serial cable with a male DB-25 connector on one endand a connector on the other end that is appropriate for yoursynchronous serial port. Your modem provides an EIA-232 interfacethrough its serial port.Transmit and Receive synchronous timing pins are required at the EIA-232interface, so pins 15 and 17 are required. The modem transmits timingsignals through pin 15 and receives timing signals through pin 17Note: The serial cable included with your modem only supportsasynchronous mode.CommunicationsSoftwarThe devices at both ends of the link must use the same synchronousprotocol.Ask your network administrator about the software support (for examplea specific communications package) that you need to log into thenetwork.SynchronousOperationsDuring synchronous operations, transmit and receive clocks at both endsof the phone link control the precise timing of the data flow. Thecommunications equipment at the remote device, your modem andcomputer must all handle the data at the same speed.Your modem is usually the source of the transmit clock timing signals andsends them to your computer over the EIA-232 interface. Yourcomputer’s rate will follow the connection rates.