System information

FCD 901 48

Issue R2A, 07.2009

XMP1 Release 5.5 System Description

Polling

Aastra Proprietary Information Page 2-35

2.5.2 Polling

The polling mode permits data transmission between a master station

(polling master) and several sub-stations. Each sub-station monitors the

data transmitted by the polling master (listening). In consequence of a

"request to send" received from the polling master, each sub-station can

communicate with the latter.

Connections between sub-stations are not possible.

Figure 2.16: Polling configuration

The operating mode of the polling master and last sub-station corresponds

to the standard mode, i.e. a channel link is switched between a port and a

converter.

In the last converter of the polling link, info no. 10 "Block VF in case of

incoming b-bit" must be set in the decentral card slot data of the converter.

Note: The KZU FEK module supports the polling operation in the

not extended configuration.

In the sub-stations, port a, port b and the converter are connected via a

channel link.

Setting up a connection between the polling master and a subscriber

1. In the quiescent state, all converters are involved in a port-to-port

connection.

2. The master station wishes the setup of a connection to a sub-station

and goes off-hook. The a-bit is sent out.

3. All sub-stations now receive the incoming a-bit.

Converter

Node 1 Node 2 Node 3 Node 4

Subscr. 1

Polling master

Polling mode

Subscr. 2

Polling mode

Subscr. 3

Polling mode

Subscr. 4

Last subscriber

Polling mode