Installation, 1 bbm to bbm link – American Telecom AM64/128A User Manual

Page 9

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Installation

AM64/128A User Manual

9

4. INSTALLATION

This chapter describes the basic steps that are required to set up a system involving the Baseband Modems
(BBM's). There are two basic systems that will be considered:

(1) BBM connected to BBM
(2) BBM connected to Line Card

When considering the installation general pointers to the configuration of the BBM's are given. It should
be noted that there are many BBM parameters which may be set differently and prevent the results from
being as expected. If any results are not as discussed then chapter 5 on menu operation should be
consulted. If this still fails to resolve the problem then the internal links can be checked, see appendix B.
N.B. : The mains input voltage selector switch on the back panel of the BBM is set as default to 230V.
Dependant on the mains supply voltage, this may need to be reset to 120V.

If the BBM is set to 230V working and is plugged into a 120V supply, then the front panel LED’s will light
but no front panel display message will appear. The BBM will stay in this state until the selector switch is
correctly set.

If the BBM is plugged into a 230V supply but set to 120V working, it will not work. There is an auto-
resetting thermal fuse incorporated into the unit which will trip. In order to reset the fuse the BBM should
be unplugged and left to stand for thirty seconds. If the voltage selector switch is then set to 230V the
BBM will operate normally.

4.1 BBM to BBM Link

With no DTE or line connected to the BBM, plug the mains cord into the IEC connector, and the mains
plug into the 230V ac supply. On power up the following messages will be displayed:

Testing

for 2 seconds, all LEDs will be on

Self Test Pass

for 2 seconds, all LEDs will be on

* STATUS MENU *

for 3 seconds, all LEDs reflect status

S > LTU Not Ready

Fault LED lit, (Assuming no line connection at this point)

If the self test fails an error message will be displayed. These are explained in section 5.4.8.
The mnemonic LTU stands for Line Terminating Unit, and this should be understood (in all cases) to be the
Baseband Modem itself.

For a point to point link to work, one BBM must be set to master mode, while the other BBM is set to slave
mode (section 5.7.1). If the link is self contained, ie. there is a DTE at both ends and no other links are
involved then it makes little difference which end is which. If another link is driven then the master modem
must be connected to the external modem, (see section 5.7.3.).

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