EVB-20022 SMSC Corporation, EVB-20022 Datasheet - Page 6

• Manufacturer Part Number: EVB-20022
• Description: Industrial ARCNET AT Adapter Card
• Manufacturer: SMSC Corporation

Twisted Pair (TW) Interface
The twisted par interface uses a standard 105 ohm 24 AWG unshielded twisted pair cable. The twisted pair interface
uses RJ-11 modular connectors that follow the ARCNET Trade Association (ATA) standard pinout for twisted pair
with Phase A on Pin 3 and Phase B on pin 2. The following guidelines for bus topology should be used for twisted
pair interface:
The line must be terminated at each end of the cable with a 105-ohm impedance. Stubs or drops are not allowed in
the TP interface. The cable segments should be connected is a daisy chain fashion. The TP interface operation is
valid only for 2.5Mbs and uses the TMC ACPWR (U11).
To setup the board for twisted pair interface, with the use of SMSC DEMOAT software, perform the following steps:
Note:
Note:
SMSC UG - EVB-20022
1.
2.
3.
1.
2.
3.
4.
5.
Make sure JP9, JP10, JP11, JP12 are unconnected
If socketed COM20022 (SKT1) is being utilized, U8 (alternate COM20022 device) must not be mounted on
evaluation board.
Max. distance (without repeaters)............................400’
Min distance between nodes .....................................6’
Max number of nodes (without repeaters)..............10
Install both jumpers horizontally at JP6 (RJ11 filter)
Install both jumpers horizontally at JP8 (Differential paired data)
Set jumper blocks JP13 and JP5 to A (Transmit data and receive data)
Set I/O board address as specified in I/O address selection in User Guide (e.g. 02E0)
Set Node ID as specified in Node ID selection in User Guide
S3
For proper twisted pair operation, installed jumpers denoted in black.
SKT1
S2
7
6
DRQ
JP3
5
3
1
0
7
DACK
6
JP2
5
JP4
U8
3
1
1
0
15
12
JP1
IRQ
11
10
Figure 2
9
Page 6
7
5
4
1
U15
3
JP13
A
B
C
D
1
JP5
1
U12
C
D
A
B
U13
JP7
`
U11
T1
JP12
JP10
JP11
JP6
JP8
JP9
1
1
1
1
1
1
LE
D
J2
S1
J1
CO
AX
Rev. 1/5/00