Motorola MVME712B 用户手册

Technical Specifications

A-3

the characteristics of the Autodialer.

Operating mode

Full duplex on 2-wire PSTN. 

Data rates

Low speed: 0-300 and 600 bps asynchronous. 
Medium speed: 1200 bps (+1%, -2.5%), 
character asynchronous and synchronous. 
High speed: 2400 bps (+1%, -2.5%), 
character asynchronous and synchronous. 

Modulation

Low speed: Frequency Shift Keying (FSK). 
Medium speed: Differentially Coherent Phase Shift 
Keying (DPSK). 
High speed: Quadrature Amplitude 
Modulation (QAM). 

Compatibility

WECO 103, 113, 212A, CCITT V.22, and 
CCITT V.22 bis modems. 

Digital interface

TTL/CMOS. 

Transmit carrier frequency

Originate Answer 
Low Speed: Mark: 1270 Hz 2225 Hz 

 Space:1070 Hz 2025 Hz 

Medium speed:

1200 Hz 2400 Hz 

High speed:

1200 Hz 2400 Hz 

Transmitter output level

Permissive (-10.5 dBm +/- 1.5 dB). 

Line impedance

600 Ohm +/- 10%, transformer coupled. 

Line protection

Lightning and transient protection. 

Receiver dynamic range

-10 dBm to -45 dBm. 

Carrier detect hysteresis

No less than 2 dB. 

Clamping

Mark hold upon loss of carrier. 

Line disconnect

Abort timer (30 seconds, adjustable). 
Loss of carrier (1.4 seconds, adjustable). 
DTR disconnect (80 ms after DTR is dropped). 

Scrambling/descrambling of 
data bits 

High speed only: self synchronizing using 
polynomial (1 + X-14 + X-17) per CCITT v.22. 

DTE connector

20-pin double row header.