3Com 3C10200 NBX Installation Guide - Page 229

C GUIDELINES FOR CONNECTING REMOTE AUDIO DEVICES This appendix provides guidelines for connecting a remote audio device to an NBX System. The remote audio device can be a 3Com Telephone, an Analog Line Card, an Analog Terminal Adapter (ATA), an Analog Terminal Card, a Digital Line Card, or other product. For instructions on configuring an NBX device to connect over a broadband connection (for example, a 3Com Telephone in your home, behind a DSL Router) see "Adding a Remote Telephone" in Chapter 2 of the NBX Administrator's Guide. The guidelines provided are for a single device, but the issues discussed can be scaled to cover multiple devices. The guidelines include the following topics. ■ Maximum Transfer Unit (MTU) ■ Communication Latency Requirements ■ Bandwidth Requirements ■ Installing Fax Machines with ATAs Maximum Transfer Unit (MTU) The system requires that the interconnection mechanism provide an apparent MTU of a full size IEEE 802.1 packet (1514 bytes of information plus 4 byte CRC). The interconnection can fragment packets into smaller frames but must reassemble the packets prior to delivery to any NBX device. The NBX devices do not presently support IP (or other) packet fragmentation and reassembly.