Case Communications Mayze 24, Справочное руководство, Страница: 139 / 166

Appendix A Modem Specification
Transmitter/Receiver
Modulation V.22bis QAM 1200, 2400 bps.
V.22 DPSK 600, 1200 bps.
V.23 FSK 1200/75, 75/1200, and 1200/1200 bps
half-duplex.
V.21 FSK 300 bps.
Carrier V.22bis: Answer 2400 Hz, originate 1200 Hz.
V.22:
Answer 2400 Hz, originate 1200 Hz.
V.23: Forward channel 1300 Hz (m), 2100
Hz (s); backward channel 390 Hz (m), 450
Hz (s).
V.21: Answer 1650 Hz (m), 1850 Hz (s);
originate 980 Hz (m), 1180 Hz (s).
Carrier Threshold –6 dBm to –43 dBm.
Operation 2-wire synchronous or asynchronous.
Output level Selectable –4 dBm to –15 dBm (UK versions set to
–9 dBm for PSTN operation or –13 dBm for leased
line operation).
Data Input Serial binary. Complies with ITU-T V.28.
Accepts levels
+
3 volts to
+
25 volts (space), and –3
volts to –25 volts (mark).
Single wire ground return.
3000 to 7000 ohms load.
Data Output Serial binary. Complies with ITU-T V.28,
+
12 and –12 volts nominal.
Output impedance 300 ohms.
Synchronisation RTS/CTS delay dependant on modulation format.
Equaliser Automatic adaptive equaliser in V.22bis and V.22
modes.
X460-306851 Issue 1 A-1 Rev.1