System information

FCD 901 48
Issue R2A, 07.2009
XMP1 Release 5.5 System Description
Central Unit
Aastra Proprietary Information Page 9-3
Table 9.D: Central Unit
9.4 Central Unit
9.4.1 RS485 interface
(Only with Central Unit QD2 and Central Unit GN/QD2)
Electrical features EIA standard RS-485 (V.11)
Bus system
Serial bus system acc. to EIA-RS 485,
half-duplex
Length of drop line to bus subscriber max. 2.5 m
Maximum bus length 500 m
Bus terminating impedance 120 Ohms
Maximum capacitive load 250 pF
Transmission rate 64 kbit/s
Signal shape NRZI (Non return to zero inverted)
9.4.2 RS232 interface
F-interface with SOX and MSP (Central Unit QD2)
Electrical features ITU-T Rec. V.24; DIN 66259, part 1
Connector 9-pin Sub-D socket
Maximum length of connecting cable 15 m
9.4.3 Clock interface T3in
Frequency 2048 kHz
Input impedance
highly resistive, balanced
1.6 k 60 pF, switchable to 120 Ohms
Voltage level U
P0
1.9 V. . . 0.5 V
9.4.4 Clock interface T3out (T4) to ITU-T G.703, 11/2001
Frequency 2048 kHz
Input impedance highly resistive, balanced
Voltage level U
P0
1.5 V 20% across 120 Ohms, resistive
Signal shape rectangular
Terminating impedance 120
, balanced
Reflection loss
16 dB at 2048 kHz across 120 resistive
9.4.5 Alarm interface
Alarm contacts for A-alarms and B-alarms
Maximum switching voltage (SELV circuit) -60 V
Maximum current 1 A