Mike's PBX Cookbook

Analog Trunk Module DIP Settings

There are two 'Global Analog Trunk Module' models:

bcm_gatm4.pngGATM 4: four analog trunk ports. Each port uses one line in the DS30 bus offset. Because each DS30 bus has four lines per offset, you can assign a maximum of four GATM4s to a single DS30 bus by making the offset switch settings different for each MBM.

GATM 8: eight analog trunk ports. Each port uses one line in the DS30 bus offset. Because each DS30 bus has four lines per offset, you require two offsets for each GATM 8. You can assign a maximum of two GATM 8s to a DS30 bus by making the offset switch settings different for each.

There are two sets of DIP switches located on the rear of the GATM:

Country select DIP switch settings
12345678Country
off off off off off off off off Download based on profile
off off off off off off off on North America (600 ohms)
off off off off off off on off Taiwan
off off off off off off on on Austrailia
off off off off off on off off United Kingdom
off off off off off on off on North America (900 ohms)
GATM Rear view:

GATM4/8 Rear view

For BCM 3.5, ensure all Country switches are off.

Note: BCM50/450: Module Mode DIPs are set to the default - ALL "ON"- position, and must
be must be assigned to a pseudeo slot number in Resources ➤ Telephony Resources.

Mode select DIP switch settings
DS30
bus #
Offset positionsDIP Switch Settings
GATM4GATM8123456
200  onononononon
11 ononoffononon
22 onoffonononon
3  onoffoffononon
300  onononononoff
11 ononoffononoff
22 onoffonononoff
3  onoffoffononoff
400  ononononoffon
11 ononoffonoffon
22 onoffononoffon
3  onoffoffonoffon
Mode select DIP switch settings
DS30
bus #
Offset positionsDIP Switch Settings
GATM4GATM8123456
500  ononononoffoff
11 ononoffonoffoff
22 onoffononoffoff
3  onoffoffonoffoff
600  onononoffonon
11 ononoffoffonon
22 onoffonoffonon
3  onoffoffoffonon
7***00  onononoffonoff
11 ononoffoffonoff
22 onoffonoffonoff
3  onoffoffoffonoff

After setting the DIP switches on a media bay module, install it in the BCM or an expansion unit - all bay slots are the same.

When adding a module, remember to tell the system what type of module is installed on each bus:

If a module status LED continues to flash, you have either an addressing conflict (check DIP switches), or a faulty module.

Remember, the BCM must be shut down before inserting or removing modules.

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