Lucent Technologies DEFINITY Installation For Adjuncts And Peripherals page 48

DEFINITY ECS Release 8.2
Installation for Adjuncts and Peripherals 555-233-116
4 Data Modules and Asynchronous Data Units
Understanding RS-232 communications
The RS-232 communications protocol defines a communications link as a Data
Communications Equipment (DCE) device and a Data Terminal Equipment (DTE)
device connected by an RS-232 cable. The send and receive pins on DCE
equipment (pins 2 and 3) are reversed on DTE equipment, so that the DCE
transmit pin connects to the receive pin of the DTE and vice versa.
Generally, the term DCE is applied to devices that mediate between customer
equipment and the carrier or network. Such devices include modems, data
modules, and data units. DTE describes devices that provide a user interface for
data communications, such as dumb terminals and PCs. When configured as
DTE, data modules are used for asynchronous modem pooling. When configured
as DCE, data modules are analogous to modems in that they link a device such
as a terminal or PC (DTE) to DEFINITY.
To install a data module correctly, you identify the connected equipment as DCE
or DTE and do one of the following:
Configure the modem for a DTE or DCE connection
Install a null-modem converter
Detailed instructions are provided in the sections for each modem type (below).
cydfnst RPY 070397
1. 103A connector or modular wall jack
2. 400B2 adapter
3. Rear of data module (7400B Shown)
4. Host computer
5. Data module power supply
6. Electrical outlet
7. Display telephone
8. S101A speakerphone
Figure 10. Typical Connections to a data module
Phone Line
Power
9. Auxiliary power supply for telephone
10. D7AP cord
11. D8W cord
12. Line to display telephone (D8W cord)
13. Data cable (EIA/RS-232)
14. Data-module power cable
15. To MDF and system cabinet
16. Printer
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April 2000
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