Data Comm for Business, Inc.

Your Complete Data Communications Solution Provider

Product Application Note


DCB distributors often come up with innovative network designs using DCB equipment and expertise. The system shown below piggybacks a new DCB private frame relay network on top of an existing network. This innovative solution delivers fast implementation and substantial savings on monthly phone line costs.


The customer, a company selling industrial tools, has an existing RS-6000 system that uses 56 Kbps DSU's to connect the async I/O devices (RANS) to six remote sites. As it happens, the DSU's are capable of multiple port TDM operation.

A second application required deploying, for a related tool repair company, terminals from an SCO Unix system to the same six remote sites.


The new network piggybacks on the existing network, using a private frame relay network and the existing DSU's. The second port of the DSU's connects the new SCO Unix application to DCB SR multiplexers at the remote sites. At the host, six separate point to point composites are combined via private frame relay and delivered to the host SRX 32 port multiplexer. The frame switches have four ports and one composite each, requiring two switches, as shown.
Figure One.

Since the RS-6000 and the SCO Unix system are several hundred yards apart, a 56 Kbps private wire DSU link bridges the distance in the home office building.

Thanks to Steve McNeer, Omaha, Nebraska for the business and the innovative design.

Data Comm for Business, Inc. is a manufacturer and distributor of a diverse line of data communications and networking products. Their experts can help you connect remote sites with phone (1-800-4-dcbnet), email (, or personal (807 Pioneer, Champaign, Il. 61820) assistance. Check out their Web page at .