DataComm V.34 PL, Operation Manual

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Operation Operating Procedures
060R115-000 DataComm V.34 PL Modem 3-7
Issue 1 Installation and Operation
Private Line Operation [FAC0 - FAC3 or USr0 - USr3]
The DataComm V.34 PL modem is configured to operate over a point-to-point, unconditioned,
voice grade private line (speech band leased line).
Point-to-point private lines rented from the telephone company are dedicated, direct, semi-
permanent phone line connections between two locations. In applications that require a continuous
data transfer between fixed points, it may be more economical to rent a private line at a fixed rate,
than to pay monthly long distance charges for dial up calls. The communication link between two
multiplexers will generally involve a modem operating over private lines.
Two-wire or Four-wire Selection
The DataComm V.34 PL modem is capable of operation on private line networks, using either 4-
wire or 2-wire circuits.
In any private line connection, first designate one modem as the originate modem
FAC0
(4W)/
FAC2
(2W) and the other as the answer modem
FAC1
(4W)/
FAC3
(2W). Next, configure both
modems for the type of communication they are intended to perform: these include synchronous or
asynchronous modes, DTE data rate, etc.
Data Mode
The DataComm V.34 PL modem is in data mode while it has a telephone line connection to another
modem or is in the process of establishing a connection. In Data Mode the modem transmits all the
data it receives from the DTE over the phone line.
In data mode the modem can operate either asynchronously or synchronously.
Each telephone line connection (private line) between two modems in data mode begins with a
handshaking sequence. During that sequence the modems determine the VF (telephone line) speed,
and related parameters for the data link. Configuration determines the range of choices available to
the modem in the negotiation process.
The presence of a carrier from a remote modem causes the DataComm V.34 PL modem to enter
data mode and assert a Data Carrier Detect (DCD) signal to it’s DTE.
Asynchronous Operation [OP.A]
When you select asynchronous operating mode (
OP.A
from the front panel), the DataComm V.34
PL modem operates asynchronously while on-line (data mode - connected to the telephone line).
Synchronous Operation [OP.S]
Selecting OP.S from the front panel selects synchronous operation.
V.13 Simulated Carrier Mode [CA.S]
V.13 mode is a simulated controlled carrier mode designed for polling applications. It uses the ITU-
T V.13 RTS/DCD signaling method to control the remote modem's DCD lead via the local modem's
RTS lead. It can be used for both synchronous and asynchronous data. To select this mode from the
front panel, select
CA.S .