User`s guide

8–2
8
Leased Line Operation
Before choosing your line, consider these issues:
❑ Whether your application would be better served
by a two- or four-wire leased line (SX-Series
modem is required for 4-wire leased line and SE-
Series will operate on 2-wire leased lines).
❑ How the telephone company terminates the
line—terminal block (spade lugs connectors) or
modular connector (RJ45 type connector
receptacle).
❑ Which modem will be used for answering and
which for originating (S0=1, S0=0).
❑ Modem line speed required (S37, Nn).
❑ For asynchronous communication, data bits,
parity, and serial port speed (%Xn).
❑ For synchronous communication, internal or
external clock source, V.13 switched carrier
requirements (&Xn, &Cn).
❑ Automatic dial backup if the leased line goes
down (S42).
❑ Automatic return to the leased line once it is
repaired (S17, S20).
There are two types of domestic line termination
provided by the telephone company. A 42A terminal
block requires a telco cable with spade lugs; a modular
JM8 block requires a modular connector (RJ45).
Overview Setup Procedures
All leased line setups involve:
❑ Running an optional leased line cable from the
modem to the leased line terminated wall jack
❑ Opening the modem's case to properly set the
jumpers inside