Comdial G0408 Manual page 69

IMI66–107
If you experience difficulty in establishing a communications path between your VDT, modems,
and the digital telephone system, note the following suggestions:
• make sure that you have enabled the modem auto-answer feature,
• confirm that the modems are wired correctly. Reverse connections at pins 2 and 3 if
necessary,
• check the modem's instruction manual. You may have to make additional wiring
connections,
• sometimes you must strap pin 4 to 5, or pin 6 to 7, or pin 6 to 8 to 20 in the modem wiring.
Check the modem's installation manual for this requirement,
• use a breakout box data tester to troubleshoot the data communications lines.
Video Display Terminal Or
Personal Computer
Data
Modem
Station Connector Block Data Ports
(4-Line, 8-Station Base Unit and
8-Line, 16-Station Base Unit)
RS232
DATA
{
PORT A
CTS
{
RS232 CTS
DATA
PORT B
Data
Jack
Network
Jack
25
50
37
TD
38
RD
39
SG 40
41
TD
42
RD
43
26
44
SG 1
45
46
47
48
49
50
CLIP TERMIINALS
Figure 2–18: Installing a Video Display Terminal
Typical Common
Equipment Cabinet
Line
Port
Telco Network
Data
Network Jack
Modem
DATA CONNECTIONS
SYSTEM MODEM
DATA PORT DATA JACK
CTS --
RD TD
TD RD
SG SG
System requires that the CTS
pin be at a high logic level
before it will send data. It will
force the pin high if no modem
connection is supplied.
Digital Telephone System
Data
Port
Line
Switch
Data Jack
Modular Jack Data Ports
(16-Line, 32-Station Base Unit)
RS232
DATA PORTS
6 5 4 3 2 1
(Front View of Jack)
1 = --
2 = CTS
3 = RD
4 = TD
5 = SG
6 = --
CAJS013
Installing The DSU 2 – 39