C G UIDELINES FOR CONNECTINGREMOTE AUDIO D EVICESThis appendix provides guidelines for connecting a remote audio deviceto the NBX 100 Networked Telephony Solution. The remote audio devicecan be a 3Com Telephone, an Analog Line Card, an Analog TerminalAdapter (ATA), an Analog Terminal Card, a Digital Line Card, or otherproduct.For instructions on configuring an NBX device to connect over abroadband connection (for example, a 3Com Telephone in your home,behind a DSL Router) see “Adding a Remote Telephone” in Chapter 2 ofthe NBX Administrator’s Guide.The guidelines provided are for a single device, but the issues discussedcan be scaled to cover multiple devices. The guidelines include thefollowing topics.■ Maximum Transfer Unit (MTU)■ Communication Latency Requirements■ Bandwidth Requirements■ Installing Fax Machines with ATAsMaximum TransferUnit (MTU)The system requires that the interconnection mechanism provide anapparent MTU of a full size IEEE 802.1 packet (1514 bytes of informationplus 4 byte CRC). The interconnection can fragment packets into smallerframes but must reassemble the packets prior to delivery to any NBXdevice. The NBX devices do not presently support IP (or other) packetfragmentation and reassembly.
