Caller ID is an interesting area and we see a variety of client request regarding this functionality. On analog lines, there is not much room for configuration. Generally this information is transmitted as FSK (i.e. modem tones) in either the SDMF or MDMF format, in the silent portion of the phone company “ring cycle”. For this reason, if you answer an incoming call before the ShoreTel has an opportunity to capture the CID information, you may not see it displayed. Unlike a PRI, outbound caller ID is controlled entirely by the phone company on analog lines and ShoreTel can do nothing to change what is displayed when you call out of the system. Sometimes, if you have a number of analog lines, the phone company displays a different Caller ID on each line! If you ask nicely, and the moon and starts are in perfect alignment with Mars, the carrier might agree to have all of your analog lines display the main Billing Telephone Number or BTN of the client account. At the end of the day, outbound caller id, is what it is on analog lines.

On PRI lines, we have more control over what is displayed when you place a call to an outside party. Generally, in ShoreTel you can display either the main PRI number of your personal DID number. We have been able to spoof the PRI D channel and display any phone number you may want on an outbound call, by configuration of the Caller ID field in the Shoreware Director administration portal under Individual Users.

We are often asked if it is possible to display a different outbound caller ID on a call per call basis. Unfortunately, unless you are willing to reconfigure the Caller ID field this is difficult, but not impossible to do. ( I know at least one police department and a half dozen credit and collection agencies that do this when the called on suspects might not answer the phone unless they know that Mom is calling)! Sometimes a company has multiple Brand names or company names that they are using when they place phone calls. To enable call by call, outbound CID change, we create Bridged Line Appearances or BLA’s. These BLA’s can be configured with a different called ID and the client can select the appropriate line (read Brand) to generate the correct CID on a particular outbound call. As an aside, we note that the carriers are getting more particular about D channel spoofing of CID on PRI calls. On SIP trunks it is all but impossible. The Carriers now insist that the displayed number must be a number that is within your BTN range. This limits spoofing.

Trouble shooting inbound (or outbound, for that matter) Caller ID calls on a ShoreTel PRI is fairly straight forward. Minimally, you can use the Trunk Test tool to witness the caller ID of an inbound call. To tap the actual D channel messages sent by the carrier to your ShoreTel SGT1, you will need to setup a capture. To do this, you will need to take the following steps (see video below):

(a) Turn off the Telnet Security Shell via the ipbxctl command

(b) Telenet into the ShoreTel SGT1 switch;

(c) For Analog & T1 turn on the mpm_debug_mask=-1 command

(d) For PRI use mpm_debug_mask=0X40 for called ID and Name.

Unlike the early versions of ShoreTel debug routines, the CID and call setup information is reasonably intuitive to decipher. Traces can also be used to figure out who hung up on who and other carrier CPE shoot out questions. These are useful trouble shooting tools.

Lastly, we need to make sure we understand the difference between ANI (automatic number identification) and Caller ID. ANIS is tariff differently and is not subject to the same blocking restrictions as caller ID number. Generally, if you are paying for “toll free” numbers, you want to know who is calling! The carrier delivers the information in a format that looks like <DID> <DNIS> * <ANI> * <DID/DNIS> and the SGT1 can note the *delimiter and sort this out. You should also be aware that ShoreTel will attempt to route the call based on a selection priority that starts with DNIS, DID, Extension and finally Tandem Trouncing. If no match is found, the inbound call will be routed to the “destinations” specified for the trunk group, with the automated attendant being the default.