Specifications

LONWORKS® LN-Series Network Communication and Interface Guide Technical Bulletin10

Network Topologies

The physical routing of the communication channel defines the network topology.

The channel and transceiver type defines the requirements and limitations of each

wiring topology.

Some network segments such as the TP/FT-10 and TP/XF-1250 require

termination for proper data transmission performance. Free topology and bus

network topology differ in their termination requirements. The following sections

describe the various network topologies, their terminator types, and termination

procedures.

Bus Topology

A bus topology is a physical routing of the communication channel that includes a

distinct beginning and end. This type is also known as a daisy-chain topology.

Network Termination

For bus topology type networks, use the following terminators at each end of the

bus topology channel (two terminators per channel in total):

Table 2: TP/FT-10 Bus Topology Network Termination

Termination Requirements Johnson Controls® Part No.

R1 = 105Ω, ±1%, 1/8 W

C1 = 100µF, ≥ 50 V

C2 = 100µF, ≥ 50 V

NXM-TERM-FTT

Table 3: TP/XF-1250 Bus Topology Network Termination

Termination Requirements Johnson Controls Part No.

R1 = 59Ω, ±1%

R2 = 340Ω, ±1%

R3 = 102Ω, ±1%

C1 = 0.15µF, ±10%*

C2 = 0.33µF, ±10%*

*Capacitors are metal

polyester, 50 V

NXM-TERM-1250

1. The NXM-TERM01250 is a discontinued product.

Figure 8: Bus Topology