AT&T Merlin II Feature Module 2 Data Communications Manual page 51

Modem Configuration Connected to an Analog Station Jack
3-14 Modem Pools
Figure 3-10 is a connectivity diagram that shows a modem pool member
connected to an analog station jack. This configuration requires a BTMI.
FIGURE 3-10 A modem pool member with a BTMI connected to an analog
station jack.
1 A 4-pair modular cord connects the BTMI to a station jack on a
4-Line/8-Analog Voice Terminal (408) Module or an 8-Analog Voice
Terminal (008) Module at the control unit. The maximum cable length is
1000 feet.
2 A 2-pair modular cord connects the BTMI and the modem. The maximum
cable length is 50 feet.
3 Standard RS-232-C connectors and cable connect the MTDM to the
modem. The maximum cable length is 17 feet.
4 A 4-pair modular cord connects the MTDM to an 8-DigitaI Station (008D)
Module jack at the control unit. The maximum cable length is 1000 feet.
If a number of MTDMs are to be connected at a common
NOTE
location, you can put as many as eight in one multiple mounting
rather than installing each in a stand-alone mounting. A multiple
mounting reduces the number of ac power sockets needed to power
the MTDMs. See the documentation that came with your MTDM for
information on the multiple mounting connections.