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12.03 DlUs can function with DCE and DTE de-
vices at data speeds of up to 19.2 kbps. However,
keyboard dialing using AT commands (from a PC
or terminal connected to a DIU) is limited to 9600
bps. A speed of 19.2 kbps can be achieved when
dialing from a PDIU-DI-equipped digital telephone
dialpad, but many PC software programs do not yet
handle 19.2 kbps in an error-free manner. DIU data
transmisssion speed is set by the first ATcommand
that the DIU receives once it is in the command
state; if manual dialing or receiving calls in the auto
answer (default) mode, the transmission speed is
transparent.
IMPORTANT NOTE!
To use the PDIU-DI or PDIU-DS with AT
commands, communications software or a
PC program that performs terminal emula-
tion must be used. A Tcommands cannot be
issued from the computer’s operating sys-
tem prompt.
12.10 Common DIU Connections
12.11
The block diagram in Figure 8-25 illustrates
common DIU connections. In this example, PDIU-
Dls are connected to personal computers (PC1 and
PC2), and PDIU-DSs are connected to a serial
printer and modems. The personal computer users
can transfer files internally, print files on the same
printer, and access the modem pool to send/re-
ceive data to/from an external personal computer
or dial up data service.
12.12 To access these devices, a data call connec-
tion must be established between the DIUs. This is
accomplished by dialing the destination DIU from a
digital telephone dialpad or from a PC keyboard
using standard AT dial commands. PDIU-Dls share
the same intercom numbers/ports with the digital
telephone to which they are connected, while PDIU-
DSs have their own. The INT and DATA LEDs on the
digital telephone tell the system whether a voice or
data call is being made: the INT LED, voice calls; and
the DATA LED initiates data calls. When dialing from
a keyboard with AT commands, B 0 1 is typed for
voice calls, and 10 m w for data calls.
12.13
Installation instructions for these devices
are provided in Paragraphs
12.40
thru
12.70.
Call
INSTALLATION-PERIPHERALS
SECTION 206-096-208
FEBRUARY1991
paths and scenarios for five types of data test calls
are provided in Paragraphs 12.82 N 12.86. Step-by-
step data calling procedures are provided in the
Data Interface User Guide in the Installation &
Maintenance Manual, Operating Procedures.
12.20 EIA Interface Leads (Signals)
12.21
Both DlUs operate with the ten standard EIA
RS-232 interface leads (signals) on which signal-
ing data is transmitted and received. DlUs connect
to serial data devices with standard RS-232 cables,
available from telephone supply stores (see Fig-
ures 8-29 m 8-34). The PDIU-DVPDIU-DS requires
ten signals for some applications, but can function
with eight using modular cords and connectors with
RJ45/DB25 adapters for other applications. If un-
certain which signals are necessary for an applica-
tion, all ten should be connected.
IMPORTANT NOTES!
1. The PDIU-DI is always a DCE device;
the PDIU-DS may be a DTE or DCE,
depending on how its internal jumpers
(I- 9) are configured (see Figure 8-28).
2. In the descriptions below, when a sig-
nal is ON, its potential is
about
seven
volts positive relative to signal ground
(pin 7); when a signal is OFF, it is about
7 volts negative relative to the signal
ground (pin 7).
l
Frame Ground (FG, Pin 1):
The FG signal (EIA
circuit AA) is a protective or safety ground which
is bonded to the PDIU-DI/PDIU-DS PCB. If re-
quired by local codes, the FG should be con-
nected to external ground.
l
Signal Ground (SG, Pin
7): The SG signal (EIA
circuit AB) establishes the common ground ref-
erence for all other PDIU and data device signals
and must be wired for all applications.
l
Transmit Data (TD, Pin
2): DTE devices trans-
mit and DCE devices receive data on the TD lead
(EIA circuit BA). Before the DTE device can
transmit the TD signal, the RTS, CTS, DSR, and
DTR signals (all discussed below) must be ON.
The TD signal is OFF in the idle state.
l
Receive Data (RD, Pi’n 3):
The DCE -device
transmits data to the DTE device on the RD lead
(EIAcircuit BB); the DTE receives dataon the RD.
8-39