Incomming calls not working

Hi all,

I’m having problems with incomming calls from the telco to my asterisk pbx that aren’t working. Here is the diagram:

Telco line-----------[Siemens HiCom 300E]-------=====IAX2=====------[Siemens HiPath 4125]

The links between the Asterisk boxes and the Siemens units are E1. The Siemens units are setup as Master clock sources. The Asterisk boxes are setup as slaves.

When a call comes in via the Siemens HiCom 300E PBX with a CallerID, the asterisk box drops the call with a “Protocol Error (6)”. If you call again with a hidden CallerID, the asterisk boxes picks the call up and passes it to where it needs to go.

The Siemens HiCom 300E is using ECMA.1

Any ideas or help will be appreciated,