It is my understanding that the problem is not OSV, but rather the RG87xx. In this specific scenario, your PSTN vendor sends "PI=2" which tells your gateway to disconnect, so OSV disconnects. This problem is not just a Siemens problem. With all the different combinations of gateways, trunking variations, and PSTN vendors, it is probably not possible for ANY single gateway to be able to handle every scenario in every country, as telecomm technology is changing rapidly.
Your RG8700 is (hopefully) set to the country code "UK", where the progress indicator (PI) values you have mentioned are apparently hard-coded. The RG is expecting an "8" but your vendor sends a "2".
To prove to you that this is a telecomm-wide problem and not just a "TDMman" problem, see this US patent document for Cisco:
It describes your EXACT scenario. Did it resolve their particular problem? I do not know!
If Siemens says that the RG is working as designed, then that is a valid response, as the RG was no doubt designed to accommodate the typical UK PSTN PI response, which is apparently "8". Your posts indicate that unfortunately 2 UK PSTN vendors have strayed from the UK norm, and they use a different value, "2", which instructs the RG8700 to disconnect. The RG is doing what is was designed to do: follow the "PI" instructions from the PSTN vendor!
Have you attempted to speak to your telecomm vendor? Perhaps the vendor can revise that specific PI within your circuit(s). If not, the they, too, will probably indicate that their ISDN is "working as designed"! Perhaps you could request a site-specific patch for the RG8700, or perhaps even a OSV patch. For example, if the RG receives a PI=2, and sends a corresponding SIP signaling command to OSV, a parameter in OSV could be manually configured to determine whether "PI=2" means "disconnect" or "open audio path" per ENDPOINT (RG8700). Have you considered using a different PSTN vendor which DOES use PI=8 for this scenario? Perhaps you could try a different gateway, such as the HiPath 4000 RG8300. Do you have a HiPath 4000 AP3700-9 IP shelf with AP-E stuffed into storage? It can be transformed into a RG8300 gateway!!! There's also the third-party Mediatrix gateway, which handles E1 and converts to native SIP (what you need), but I do NOT KNOW if it properly handles your PI=2 versus PI=8 problem. You would need to consult with Mediatrix before spending money. Their website is:
Did you purchase this telecomm system from Siemens? Perhaps they are willing to participate in an experimental exchange of RG87xx and Mediatrix.
In summary: your problem is not "specific" to Siemens, but rather is an ISDN<>SIP problem. Cisco has definitely experienced the problem as detailed in the patent application. With rapidly changing telecomm technology, these inconsistencies are going to happen - but unfortunately this one has negatively impacted YOU. You have options. Think positive, and please re-post WHEN you get the issue resolved.
