Modem Pools - AT&T Merlin II Feature Module 2 Data Communications Manual

Modem Pools

MODEM COMPATIBILITY
AND MODEM
MTDM
OPTION SETTINGS
3-12 Modem Pools
Modem pools allow many digital endpoints to share a limited number of
modems for incoming and outgoing data calls. Your Master Planning Form,
Data Hunt Group Form, and Incoming Modem Poo1 Form list the control unit
jacks that should be assigned to each modem configuration that is a member
of a modem pool. The forms also provide other information about the
modem pools, such as whether a' modem pool is incoming or outgoing and
what type of modem is used.
Each modem configuration in a modem pool includes the following:
• 2212C or other compatible modem
• Modular Trunk Data Module (MTDM) with RS-232-C Interface
An MTDM is a DTE device that seines as an interface between the control
unit and a modem. With the modem, it changes digital data signals from the
switching facilities to analog signals that can be transmitted over standard
telephone lines, and vice versa.
If the modem is connected to an analog station jack rather
NOTE:
than to a basic telephone jack or a dedicated outside line, it requires a
Basic Telephone and Modem Interface (BTMI).
The diagrams that follow show typical configurations for modem pool
members connected to:
Basic telephone jacks at the control unit
Analog station jacks at the control unit
Dedicated outside lines (lines that aren't connected to the MERLIN II
system control unit)
See "General Requirements for Modems in a MERLIN II System" for
information on using modems other than the 2212C modem in the MERLIN II
system.
Be sure to set the option switches on your equipment as described in "MTDM
Option Switches" and "2212C Modem Options" before activating modem
pools.