About the Modem

In leased line operation, while connected on the dial line, the modem can monitor for LPDA2 commands in the data stream. If the local modem detects an LPDA2 command, the frame that is being processed is aborted. This prevents the remote DTE from processing the command frame as valid data.

Refer to Chapter 3, Automatic Calling Interfaces, in the 326X Series Modem

Reference Guide, for details.

Managing a Modem

Integral Network Management by Motorola’s 9110, 9000-UX, and 9000-PC Network Management Systems (NMS) is standard. The NMS can configure, moni- tor, and control local and remote modem operation.

An NMS continuously polls modems to collect management information and check status. Network management traffic, including alarms, commands, events, and polling, is transported to remote modems on an in-band channel that does not disrupt user data traffic nor consume user bandwidth. The modem supports a daisy-chain network management interface, reducing the hardware required for connections.

Refer to Chapter 2, Installing the Modem, for instructions on installing and cabling a modem for use with Motorola’s Network Management Systems.

Restoring Data Transmission

For critical leased line applications that require backup, you can use Models 3261, 3263, 3266, or 3268 in a point-to-point configuration. If the leased line fails, these modems can automatically reroute data traffic through the public switched telephone network (PSTN) over a 2-wire dial line. This integral dial line restoral feature guarantees that data will keep flowing, minimizing network downtime.

ITU-T V.34 Compliant Modulation Mode

326XFAST and 326XFAST-SDC modems support the ITU-T V.34 compliant modulation mode. 326XFAST- SDC modems offer the same broad set of features available in the 326XFAST modems, and let you take advantage of faster transmission speeds while providing highly reliable data transmission in full-duplex synchronous environments.

326XFAST modems have a line probing feature that optimizes performance on every connection by automatically choosing the optimum bandwidth, carrier frequency, and data rate.

V.34 Modulation Mode Characteristics

V.34 modulation mode characteristics are as follows.

1-6 About the Modem

Page 30
Image 30
Motorola and V.32bis, V.34-SDC manual Managing a Modem, Restoring Data Transmission, ITU-T V.34 Compliant Modulation Mode