Specifications

Introduction
MP2100M-LS-2 Modules - Installation and Operation Manual 1-9
Because of the use of synchronous-to-asynchronous conversion, when
configuring the individual channels, it is necessary to select the DCE timing
mode for asynchronous channels.
In the asynchronous mode, the user can select the word length (8 through
11 bits) using an internal DIP switch. The required word length is obtained the
adding the number of start bits, data bits, parity bits, and stop bits generated by
the user's asynchronous equipment. The bits are transparently transferred, e.g.,
when parity is used, no parity check is made by the channel.
The word length can be independently selected for each channel group, as
explained above.
Characteristics of
LS-2/M Channels
The LS-2/M channels have built-in modems, which are intended for operation
over unconditioned 4-wire telephone loops (two twisted pairs). Typical ranges
are as follows:
• At the highest channel data rate, 19.2 kbps, typical ranges are up to 10 km
(6.25 miles) over AWG 19 (0.9 mm) pairs, up to 4.5 km (2.8 miles) over
AWG 24 (0.5 mm) pairs, and up to 3.0 km (1.8 miles) over AWG 26
(0.4 mm) pairs.
• At 2.4 kbps, typical ranges are up to 15 km (9.3 miles) over AWG 19
(0.9 mm) pairs, up to 6.5 km (4.0 miles) over AWG 24 (0.5 mm) pairs, and
up to 5 km (3.1 miles) over AWG 26 (0.4 mm) pairs.
Each of the LS-2/M channels provides the receive timing signal to the built-in
short-range modem, and accepts a transmit clock from the modem (this timing
mode is similar to the DTE1 mode). Therefore, the LS-2/M channel determines
the timing of the data sent to the external modem.
To ensure that the same timing is used on the transmit direction (from the
external modem to the LS-2/M channel), the external modem must operate with
loopback timing. The transmit clock is recovered by the built-in modem from
the line signal received from the external SRM-8 modem.
Time Slot Routing
The MEGAPLEX system enables the user to select the main link that will carry
the data applied to the LS-2 module or module group (when LS-2 module
groups are used, the selected routing applies to all the modules included in the
group). Moreover, the user can select, for each LS-2 module or module group,
the main link time slots assigned in the corresponding T1 or E1 main link frame.
User-controlled manual assignment allows the routing of the bit stream
generated by each local module or module group to another compatible LS-2
module, respectively module group.
The LS-2/M module can also operate in a link with the MTLS-2/X.50,
LS-2A/X.50, and LS-2/X.50 ten-channel data module, provided compatible
envelope assignment is used.