Carrier WeatherExpert 48N2 Controls, Start-Up, Operation, Service, And Troubleshooting page 245

APPENDIX F — BACNET COMMUNICATION OPTION (CONT)
To install a BT485 terminator, push the BT485 terminator on to
the BT485 connector located near the BACnet connector.
NOTE: The BT485 terminator has no polarity associated with it.
To order a BT485 terminator, consult Commercial Products
i-Vu Open Control System Master Prices.
MS/TP Wiring Recommendations
Recommendations are shown in Tables L and M. The wire jack-
et and UL temperature rating specifications list two acceptable
SPECIFICATION
Cable
Conductor
Insulation
Color Code
Twist Lay
Shielding
Jacket
DC Resistance
Capacitance
Characteristic Impedance
Weight
UL Temperature Rating
Voltage
Listing
LEGEND
AWG — American Wire Gage
CL2P — Class 2 Plenum Cable
DC — Direct Current
FEP — Fluorinated Ethylene Polymer
NEC — National Electrical Code
O.D. — Outside Diameter
TC — Tinned Copper
UL — Underwriters Laboratories
Fig. L — BT485 Terminator Installation
Table L — MS/TP Wiring Recommendations
Single twisted pair, low capacitance, CL2P, 22 AWG (7x30), TC foam FEP, plenum rated cable
22 or 24 AWG stranded copper (tin plated)
Foamed FEP 0.015 in. (0.381 mm) wall 0.060 in. (1.524 mm) OD
Black/White
2 in. (50.8 mm) lay on pair 6 twists/foot (20 twists/meter) nominal
Aluminum/Mylar shield with 24 AWG TC drain wire
SmokeGard Jacket (SmokeGard PVC) 0.021 in. (0.5334 mm) wall 0.175 in. (4.445 mm) OD
Halar Jacket (E-CTFE) 0.010 in. (0.254 mm) wall 0.144 in. (3.6576 mm) OD
15.2 Ohms/1000 feet (50 Ohms/km) nominal
12.5 pF/ft (41 pF/meter) nominal conductor to conductor
100 Ohms nominal
12 lb/1000 feet (17.9 kg/km)
SmokeGard 167°F (75°C)
Halar -40 to 302°F (-40 to 150°C)
300 Vac, power limited
UL: NEC CL2P, or better
245
alternatives. The Halar
specification has a higher temperature
1
rating and a tougher outer jacket than the SmokeGard
tion, and it is appropriate for use in applications where the user is
concerned about abrasion. The Halar jacket is also less likely to
crack in extremely low temperatures.
NOTE: Use the specified type of wire and cable for maximum
signal integrity.
1. Halar is a trademark of Solvay Plastics.
2. SmokeGard is a trademark of AlphaGary - Mexichem Corp.
RECOMMMENDATION
specifica-
2