Unify OpenScape Desk Phone CP and OpenStage — setup for our PBX

These phones used to be sold as Siemens, then as Unify (the brand belongs to Mitel today). Venues run them in two generations: the newer OpenScape Desk Phone CP line (CP100, CP200/CP205, CP400, CP600/CP600E, CP700/CP700X) and the older but very long-lived OpenStage 15/20/40/60/80, continued as OpenScape Desk Phone IP 35G/55G. Setup is almost identical: both generations share the same web interface (Unify calls it WBM), the same System → Registration menu and the same factory administrator password.

⚠️ Check this before you buy and before you configure. Every Unify model ships in two firmware flavours: SIP and HFA (the proprietary CorNet-IP protocol). Only the SIP version works with our PBX. An HFA phone talks exclusively to an OpenScape Business or OpenScape 4000 system — it simply has no SIP server fields in its menu, and no setting will change that. How to tell: a SIP phone has System → Registration in the administrator menu, and the box and the phone properties say "SIP".

Shared credentials, network requirements and typical mistakes are on the overview page “Setting up SIP phones”.

What you need#

• A Unify phone with SIP firmware, cabled into the same network as your computer (powered over PoE from the switch, or from a separate power supply).
• The extension credentials from the admin panel: Admin panel → Telephony → Operators → “Reset password” — the “Extension credentials” window (details).
• A computer with a browser on the same network.
• The phone’s administrator password. The factory value is 123456; if somebody has already configured the phone, the password may have been changed — then you need a factory reset.

Step 1. Find the phone’s IP address#

By default the phone gets its address over DHCP and does not display it anywhere — look it up in the phone menu.

1. Press the main menu key (the three-bar icon) or the Settings key.
2. Choose Settings → User settings. If the phone asks for a user password — it is not set at factory defaults, just confirm.
3. Open Network information.
4. The IPv4 address line is the phone’s address; the URL line (Web address on OpenStage) is the ready-made address of its web interface.

Screenshot: OpenScape Desk Phone CP600/CP600E SIP, User Guide, p. 210.

Step 2. Log in to the web interface#

Open the phone’s address in a browser. The browser will warn about the certificate — that is normal, the phone’s certificate is self-signed; continue.

Screenshot: OpenScape Desk Phone CP SIP, Administrator Documentation, Issue 1 (05/2024), p. 28.

In the top right corner the page shows the phone’s number, IPv4 address and DNS name — a handy way to confirm you have opened the right device.

Administrator password changed and unknown? It cannot be recovered — only a factory reset helps. The vendor recommends changing the factory 123456 right after the first login (Security and policies → Password → Change Admin password).

Step 3. Enter the PBX credentials#

All account fields live on two pages of the web interface: System → Registration and System → System identity.

Three more fields on the same System → Registration page:

• SIP gateway address — leave 0.0.0.0 (we have no separate gateway);
• Server type — choose Other. The factory OS Voice enables behaviour specific to Unify’s own PBX, which ours does not have;
• Realm — leave empty, our PBX does not require it.

Press Submit at the bottom of the page. The phone applies the addresses and the account immediately, no reboot needed; if something did not take effect, use Maintenance → Restart Phone.

Screenshot: OpenScape Desk Phone CP SIP, Administrator Documentation, Issue 1 (05/2024), p. 46.

The most common mistake on these phones is putting the short extension number (“101”) into Terminal number. It is exactly this field that goes out in the REGISTER message, so it must hold the full login sip-xxxxxxxx-101, while the short number belongs in Display identity.

Step 4. Verify the registration#

• On the phone. The idle screen shows the line label — the extension number you set in Display identity. If the phone is not registered, there is no label and calls will not go through.
• In the web interface. Open Diagnostics → Fault trace configuration only if something is wrong; normally it is enough to check that the fields on System → Registration survived the Submit.
• In the admin panel. Admin panel → Telephony → Operators: the operator gets a green dot and a line with the identity the phone reported (for example OpenScape Desk Phone CP400). The status comes from the PBX and refreshes at most once a minute.
• Test call. Dial a colleague’s extension. If the call connects but only one side is audible, the problem is not registration but RTP: check SIP ALG on the router (overview).

Factory reset#

Unify phones have two different passwords: the administrator password 123456 and a separate reset password 124816. A reset is possible even when the administrator password is lost — that is exactly what the second password is for.

From the phone (works with a lost administrator password):

1. Press the Settings (Service) key to open the administration menu.
2. Press the digit keys 2 – 8 – 9 simultaneously. The factory reset menu opens. If it does not, the key combination has been switched off in the security settings (the Factory reset claw parameter) and only the web interface route is left.
3. Enter the reset password 124816 and confirm with OK.

From the web interface: Maintenance → Factory reset → type 124816 into Factory reset password → Submit. The same item exists in the phone menu: Admin → Maintenance → Factory reset.

Screenshot: OpenScape Desk Phone CP SIP, Administrator Documentation, Issue 1 (05/2024), p. 288.

What is erased: every parameter returns to its factory value — the SIP account, server addresses, network settings (DHCP is switched back on), language, time zone, programmable keys. The administrator password becomes 123456 again and the user password becomes empty.

When you cannot avoid a reset: the phone was bought second-hand or came from a previous operator (it keeps the address of somebody else’s DLS provisioning server and will overwrite your configuration on every reboot); the administrator password is lost; the phone misbehaves after a firmware update.

After the reset the phone reboots and may ask for a “Terminal number” on the screen — you can skip that and go back to step 1: it will pick up an address over DHCP again, and you will enter the whole account through the web interface.

If the phone does not register#

1. Terminal number holds the short number. This is the field that goes out in REGISTER — it must contain the full login sip-xxxxxxxx-101, the same value as User ID.
2. The login is not in every field. System identity → Terminal number and Registration → User ID must match.
3. The password is stale. The admin panel shows the password once; if you closed the window, press “Reset password” on the operator and enter the new one. The old password stops working.
4. The PBX address is only in one field. SIP server address is used for outgoing calls, SIP registrar address for registration; for us it is the same address and both must be filled in.
5. The firmware is HFA, not SIP. If the System page has no Registration item at all, you have an HFA phone — it will not connect to our PBX.
6. Transport or port were changed. System → SIP interface → SIP transport must be UDP and Network → Port configuration must be 5060. If somebody selected TLS, the port was moved to 5061 as well; our PBX does not offer TLS.
7. The phone came from a previous operator and receives somebody else’s DLS address over DHCP, which restores the old settings. Only a reset fixes this — and, if needed, disabling option 43 on your DHCP server.
8. General network causes — SIP ALG on the router, client isolation on Wi-Fi, blocked ports: see the overview.

Models in the family#

Every model listed also exists in an HFA flavour — only the SIP one works with our PBX.

FAQ#

How does the SIP version differ from HFA, and which one do I have?#

HFA (CorNet-IP) is Unify’s proprietary protocol for OpenScape Business and OpenScape 4000 systems; such a phone cannot talk to a third-party PBX at all. Check the administrator menu: if System contains a Registration item with SIP address fields, the firmware is SIP. Converting HFA to SIP is officially possible, but a Unify partner does it through their own procedure — do not count on it for a second-hand phone without a service contract.

I lost the administrator password — what now?#

It cannot be recovered, only reset. The reset itself does not need the administrator password: press Settings on the phone, then the 2-8-9 keys simultaneously, and enter the separate reset password 124816. After the reset the administrator password is 123456 again.

Do I need a provisioning server (DLS)?#

No. DLS is Unify’s own tool for configuring fleets of phones, and our platform has no provisioning server of its own: the phone is configured field by field as described here. Somebody else’s DLS, however, is harmful: a phone inherited from a previous operator may receive its address over DHCP and restore the old settings after every reboot.

The phone asks for a “Terminal number” after power-on — what do I type?#

That is the factory prompt for the phone’s number. Enter your login from the admin panel (sip-xxxxxxxx-101) — it is the same value as the System identity → Terminal number field. You can also skip the prompt and fill everything in later through the web interface.

Can I enable encryption (TLS/SRTP)?#

Not at the moment: our PBX accepts UDP and TCP, and does not offer TLS or SRTP. Keep SIP transport = UDP and port 5060.

Sources#

• OpenScape Desk Phone CP100/CP200/CP205/CP400/CP600/CP600E/CP700/CP700X SIP, Administrator Documentation, Issue 1 (A31003-C1000-M101-21-76A9, 05/2024) — https://wiki.unify.com/images/a/a3/OpenScape_Desk_Phone_CP200_400_600_SIP%2C_Administrator_Documentation%2C_Issue_1.pdf
• OpenScape Desk Phone CP600/CP600E SIP, User Guide — https://wiki.unify.com/images/5/5d/OpenScape_Desk_Phone_CP600_CP600E_SIP_User_Guide.pdf
• OpenScape Desk Phone CP200/CP205 SIP, User Guide, Issue 2 — https://wiki.unify.com/images/d/db/OpenScape_Desk_Phone_CP200_SIP%2C_User_Guide%2C_Issue_2.pdf
• Administration Manual OpenStage 20/40/60/80 SIP (OpenScape Voice) — https://wiki.unify.com/images/1/1b/Administration_Manual_OpenStage_OpenScape_Voice.pdf
• Family overview and model list — https://wiki.unify.com/wiki/OpenScape_Desk_Phone_CP