How to Implement Cisco Call Manager Express at Home, part three

The Numbers Game

There are several types of telephone numbers, known as “tags” to identify the individual extensions, sets, etc.; similar to how an Internet routing path works.

ephone for [Selsius] Ethernet Phone, or known today as Cisco IP Phone (the company Cisco acquired in the late 1990s)

ephone-dn for Directory Number (easy if you came off from Nortel)

voice register pool for a SIP Phone, whether it’s a Cisco or not

voice-register-dn the number for the SIP phones or devices

SIP and Voice Registers are in a separate post. As of this writing in 2020, the CME releases prior to 9 are essentially becoming End of Life; and SIP is now becoming the only protocol Cisco will officially support, no new models since the mid 2010s uses SCCP exclusively; though CME doesn’t work well with SIP natively if you have the 7900 series with SIP firmware. Since version 11, it only handles SIP at the desktop level, SCCP only works if you still have the VG200 analog phone gateways; or the smaller FXS cards. The more recent, 7800, 8800 and 9900 models only runs on SIP protocols. In reality, SIP is much more mature (but still not the best VOIP protocol around), and the newer generations of Cisco IP Phones with the SIP stack reflect it. The 7900 was never really intended to take all the lack of benefits to SIP and not only that the very original generations the 79×0 models limited it’s use to support BLFs, the speaker was half duplex, and the audio quality was at level of a POT set, over a set that had a Skinny firmware.

Trunk mode: Key System (“Call on Line 1”)

As much as I admire the 1A2 systems, and my poor fine motor skills, I don’t want to forget history of the largest types of systems, PBX are actually a microcosm in the telephony world. If you got a 796x, this will be easy; without loosing button space for other line appearances.

In this example, this would be a dummy extension

CORE1(config)# ephone-dn 60

CORE1(ephone-dn)# number 200

CORE1(ephone-dn)# label Line 1

CORE1(ephone-dn)# name Line 1

If you have Call Waiting and you enabled Switchook flash in telephony-service, you could set this up to be a dual-line, to achieve this, to do that, all you would need to do is add  “ephone-dn 60 dual-line” to the end if you did this already, and made a mistake you will need to remove it (using “no ephone-dn 60”  as the example) and reenter it as such.

FXO Configuration (voice-port)

Now it’s time to define that FXO port to match that dummy extension. Now you’ll branch out to the trunk level and assign various commands to make this work:

CORE1(config)# voice-port 0/1/0

Which means on the Cisco 2801, it’s on router  0, slot 1, port 0 (the female jack),  similar to 01A0401 on say a large Avaya PBX.

CORE1(voice-port)# supervisory-disconnect anytone 
CORE1(voice-port)# groundstart auto-tip
CORE1(voice-port)# timeouts-interdigit 6
CORE1(voice-port)# timeouts call-disconnect 28

I use this because the Xifinity Digital Voicemail, and if no one answers by the 6th ring, it stops ringing. If you do not have this type of timeout, the router “answers” the call and rings to the command below. If you do not insert this, the phones will “ring off the hook”. In fact it concerned one of my grandmother’s doctors who just happened to call on the same day of the final cutover, and I realized I omitted it.

connection plar opx 200

This means it will connect to a Private Line Automatic Ringdown to Off Premise Extension of 200, the ephone-dn 60 for the dummy “Line 1”. Ironically OPX must think the extensions is off premise to the router’s mind.

description Comcast POTS

caller-id enable

If say you wanted only one phone to answer the call (which this would act like a PBX, where a single point of entry), you’d use the DN that is of the extension you wanted to answer, such as say 101. For the home, it’s easier to lump sets on a dummy extension in case of some network flare up that caused a phone to go down, someone unplugged a set, etc. I’m a clumsy guy, and if you had one set go down, a busy signal would generate on the other end, because no device is able to ring.

There was some issues where the phones would ring once every 10 minutes or so. Upon a google search, I found entering the following in the config mode, this helped

voice class custom-cptone Comcast

 dualtone disconnect

  frequency 480 625

ephone-dn (Extension Number)

As previously explained, the ephone-dn is for the extension. In Release 8 and higher, there is more than just an option dual-line, but an octo-line. Octo means 8 different instances of calls can come into a CME  instance without a busy signal. Though in Cisco, your call appearances are virtual and requires juggling using softkeys and no hard keys like how Avaya is known for. With SIP, you could return back to the Avaya-style as call-waiting or appearance buttons are device-centric and not phone system specific, which in a lot of ways could be easier. In fact octo-line is designed for call-parking, which will be discussed in the future.

Depending on that PVDM that’s required to anything, even if you were just playing with commands, the more instances of calls will chew up resources on the PVDM, even if you are within the limits. This is because after you assign a Cisco IP Phone, the ephone command already populates the  lines after configuring, so that means that phone will have dedicated lines literally.

The SCCP protocol can support up to 200 simultaneous calls, but that’s more for say a UCM, and given how it can’t roll over to another idle button like an Avaya; it’s an overkill; especially when it’s line specific, not phone specific. It’s better off being a dummy extension than anything else.

Setting up Cisco IP Phones

If you did the ephone-dns for all your relevant extensions; and you’re in no hurry to add BLFs, you could in theory use auto-reg-ephone in the telephony-service function, and plug in the phones one at a time, to then to match extensions to phones. But if you want to do more, one at a time maybe your only  bet

For all intensive purposes, start with one. In config mode enter the following

CORE1(config)# ephone 1
CORE1(ephone)# mac-address 0000.0000.0000
CORE1(ephone)# type 7970
CORE1(ephone)# button 1:1
CORE1(ephone)# button 3m70

In mac-address use the MAC that is on your VOIP set that you’re adding ensure it’s split up into threes and add a “.” every 4 characters in the hardware address.

For all intensive purposes, “button 1:1” means Button 1 is tied to Directory Number 1, extension 100; button “3m70” is functioning as BLF for the dummy extension of 200 that’s acting as a Key line and is monitoring the line; you can access it and it will ring when the number receives a call. And I believe you could use 0s for MAC addresses if an event you’re waiting for a new Cisco phone to ship and use it as holding till the set arrives. I know this can be done in voice-register, but didn’t verify with ephone.


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