Table 16: KNX protocol rules
Category Rules and Maximums
Termination No termination
Manufacturer's Quality
Management System
At least ISO 9002
Table 17: Network Engine to Level Converter connection rules (M-Bus only)
Category Rules and Maximums
General Use either an RS-232 or RS-485 connected level converter or a network connected level
converter.
Number Devices Use either one serial level converter or five network level converters per trunk.
RS-232: Level converter maximum length on 15 m (50 ft)
RS-485: Level converter maximum length on 1,500 m (5,000 ft)
Line Length and Type
Network level converter: maximum length of 2,000 m (6,600 ft) for plastic/glass fiber optic
with external adapter
10/100 BaseT: 100 m (330 ft) CAT5 cable
Termination No termination
Table 18: Guidelines for LonWorks network bus topology
Cable Type Maximum Segment Length with
FTT10 Devices Only
Maximum Segment Length with
FTT10 and/or LPT10/11 Devices
11
Belden 85102 Cable 2,700 m (8,850 ft) 2,200 m (7,200 ft)
Belden 8471 Cable 2,700 m (8,850 ft) 2,200 m (7,200 ft)
Level IV 22 AWG 1,400 m (4,600 ft) 1,150 m (3,770 ft)
JY (St.) Y 2 x 2 x 0.8 900 m (2,950 ft) 750 m (2,460 ft)
Note: For the bus topology, the maximum length stub cable is 3 m (10 ft), and the stub lengths must be calculated
into the overall segment length.
1 FTT: Free Topology Twisted Pair Transceiver; LPT: Link Power Twisted Pair Transceiver.
Table 19: Guidelines for LonWorks network free topology
Cable Type Maximum Node-to-Node Distance Maximum Segment Length with
FTT10 and/or LPT10/11 Devices
Belden 85102 Cable 500 m (1,640 ft) 500 m (1,640 ft)
Belden 8471 Cable 500 m (1,640 ft) 500 m (1,640 ft)
Level IV 22 AWG 400 m (1,300 ft) 500 m (1,640 ft)
JY (St.) Y 2 x 2 x 0.8 320 m (1,050 ft) 500 m (1,640 ft)
Table 20: Maximum number of devices per LonWorks network segment
Device Type Maximum Allowed
FTT10 Nodes Only 64 nodes if repeaters are not used; 255 nodes if repeaters
are used
Mixed FTT10 and LPT-10/11 Nodes ([FTT10 x 2] + LPT10/11) < 128
Physical Layer Repeaters Maximum of 1 per segment
Terminators
Bus Topology Two bus type EOL terminators required (NU-EOL202-0)
NAE55 Installation Guide 15