BusinessPhone Communication Platform 7.0
Installation Instruction ASB 150 02 > Boards for ASB 150 02

## BTU-E (ROF 157 5113/_)

Board for tie-line (private trunk) traffic. Each board has 4 individuals with E&M signalling. Voice is transmitted via 2 or 4 wires (a/b). The following signalling formats are supported:

- E&M swedish format
- E&M continuous (A - and D - format)
- E&M discontinuous
- American E&M
- ESPA signalling to connect paging equipment
- CAILHO (transformer balanced lines with common mode DC pulse signals)
- CEPT L1
- SSAC15 (tone type in-band signalling system of BT)

#### Paging connection

The figure shows how to connect the paging equipment Ericall Contactor with 2 wire speech. The PBX sends paging information to the paging system (pin 6A18) using the M1 contact, and the information about ’paging in progress’ or ’paging equipment not present’ is received on the E1-wire (pin 6C18) from the paging equipment.

Applies for switches 109, 209, 309 and 409.

Figure showing Paging equipment and 2-wire speech with ’loop connection’ of the E&M-wires.

#### Four wire speech connection

The four wire speech and signalling connection has the benefit of not needing additional signalling wires. There are two different types of signalling supported:

1) Cailho E&M-signalling (balanced battery). The two way signalling utilises common mode DC pulses via the centre tap of the transformer. On one side a detector is connected between the -48 VDC and the centre tap of the transformer. The other end uses opto relay M4 to switch the line to 0V (Ground). The detector reads the current flow to ground every time M4 closes.

2) CEPT L1/SSAC 15 with 2280 Hz tones. In this case no DC signalling is used but instead signalling is performed by switching on and off a 2280 Hz tone, which is detected by a tone receiver on the other side. This is only available on index 2 boards.

Applies for switches 109, 209, 309 and 409.

Figure showing Cailho E&M signalling and CEPT L1 or SSAC 15 with tone signalling

#### E&M-signalling

Signalling on E & M wires is done either using one or two E&M pairs depending on what is required. Using just E1 and M1 is a very common practice. One case to mention is the American E&M signalling, where the M1 wire toggles between -48VDC and 0V.

Double E&M signalling requires the E1/M1 wires for the signalling of information and the E2/M2 wires indicate blocking of the connection. The E1/M1-wires are used for signalling and the E2/M2-wires are used for blocking. The figure shows the 0V connection to the M-wires in both ends.

Applies for switches 109, 209, 309 and 409.

Figure showing four wire speech and standard (double) E&M signalling.

Revision: J © Ericsson Enterprise 2005