Analog Recommendations

In the past handful of posts, I’ve run through some of the details on how analog devices connect to and work with, SfB. Now that the technical bits are out of the way, I wanted to provide some recommendations on how you can make life with analogs easier.

We’ve seen that analog devices really don’t become Skype for Business devices. They might as well be an extension on a PBX. If you’re not getting SfB functionality and management, and you have to buy gateways and do all kinds of extra configuration, why bother at all?

You should get rid of as many analog lines and devices as you possibly can, including faxes. 141 years of analog telephony is already too long.

There, simple enough? Well no, not really, but that statement sums up what I feel is a realistic and relevant aim for every organization deploying Skype for Business. Exceptions exist in a few cases, but in general analog needs to go.

Analog Trunks

Let’s talk first about analog trunks to the PSTN. The quality is terrible, they’re expensive in comparison to a SIP trunk channel, and they offer very poor flexibility for inbound calls. You can’t have more than one number assigned to each physical line except for when you use the concept of overlines. That means you need one line per direct phone number, and user with a direct number is limited to one call at a time. That forces you to the use of main numbers, auto-attendants, and extensions, and that’s what the 80’s were for.

For outbound calls, you have no flexibility to set caller ID. You get the individual line number, the overline number, or the telco will allow you to use the main number, but this configuration is all static, and all done through the telco.

As for emergency calls, stick a red phone on the wall beside the firstaid kit, AED, and fire extinguisher. Don’t try and use one analog line to handle emergency calls for an entire building of SfB users. In any real emergency, your users will quickly swamp one or two lines. Your Skype for Business deployment should be able to place multiple emergency calls per site, not just one or two.

Faxes and Modems

Faxes and modems work by sending sound over an analog line. The devices on either end whistle at each other. Does it really make sense to stick a piece of paper into a machine, have that machine scan the paper, then whistle over an analog line to a gateway that’s going to now digitize and packetize the audio, transmit it long distances over laggy, jittery, and potentially lossy media, then decode and reassemble that digital information back into an approximation of the original whistle, such that a second machine can listen to it and draw a picture of what is represents?

How is this still a thing that we do?


Some organizations still use faxes. It may be a legal requirement, they may have partners that still use fax, or they just might be slow to change. First, do a quick survey of your existing machines and users. Pull some reports from the machines to see how often they’re used. Find out who uses them, and what for. There’s a good chance that they could scan to PDF and email, fax directly from MS Word via an eFax driver, and receive directly to their inbox via an eFax service.

At the very least, you can probably reduce the number of physical fax machines that you have. If you do need to keep a machine around, it doesn’t need to talk to Skype for Business, so move them off your SIP trunks and PRIs to an individual analog line.


Gone are the days of modems for accessing the Internet. Every modem that I stumble across these days is a rescue – or out of band management – modem. It makes a lot of sense to have a way to reach and administer your gear, that’s independent of that same gear. Independent is the key word.  If you need a rescue modem for anything voice related, it must be a single analog line from the telco.

Better yet, ditch the analog modems. You can use an LTE stick in a device or router, or a consumer-level DSL line to a VPN headend. This approach will also give you enough bandwidth to do more than poke away at a command line.

Alarms and Elevator Phones

These too, are best moved to individual analog lines. They don’t need to talk to Skype for Business. In terms of uptime and reliability, a boring analog line from the Telco will be rock solid. Your users that get stuck in an elevator won’t be using the elevator phone when the UPS powering your SBC or gateway runs out of juice and the call drops. If you need your elevator phone to reach someone at your organization, you can route the call via the PSTN.

When You Have To Integrate Analog

Lurking in many larger conference rooms are standards based video conferencing units. Many of these have analog connections for voice calls. Depending on how old these units are, and if you’re planning to refresh them, you may be in a position to deploy some of the fantastic options that talk natively to Skype for Business for both audio AND video. If refresh/replacement isn’t near, then you may need to go down the path of analog integration into Skype for Business. The good news is that this is the simplest form of a SfB analog device.

Paging and Enterphones

This is a spot where analog in your Skype for Business environment makes sense, especially if they’re already deployed. Many paging and enterphones (“buzzers”) come in analog or SIP versions, but Skype variants don’t exist. You’re also not going to be worried about call quality or downtime due to power outages with these. Financially, these devices likely aren’t used enough to justify analog lines directly to the telco.

Skype for Business Online

If you are planning to move to Skype for Business Online, you should be aware that there is no “CsAnalogDevice” online (there’s also no CsCommonAreaPhone). You won’t be able to take advantage of how CsAnalogDevice simplifies routing, and your analog devices won’t be SfB objects that can be added to your contact list. If your analog device needs PSTN access, you will have to obtain an on-prem PSTN connection, there is no way to use a Cloud PBX with PSTN Calling number.

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