VoIP Resources VoIP Reviews Desk Phones

Cisco SPA504G

by OnSIP

The Cisco SPA504G is a mid-range business desktop phone with an extensive feature list.

Published: November 11, 2009


OnSIP Testing:star_orange_24star_orange_24star_orange_24star_orange_24star_orange_24
Voice Quality:star_orange_24star_orange_24star_orange_24star_orange_24star_gray_24
Ease of Use:star_orange_24star_orange_24star_orange_24star_orange_24star_orange_24

Quick Specs

  • 4-Line Phone
  • IEEE 802.3af PoE (Power Over Ethernet)
  • G.729 and G.722 Wideband Audio Support
  • AUX port (SPA932 or SPA500S attendant console is supported)
  • Hearing aid compatability (HAC)
  • Optional PA100 Power Adapter and MB100 Wall Mount Adapter


  • Excellent audio quality
  • Intuitive to use
  • Upgrade of the successful and now discontinued Linksys models


  • Web Admin UI may be confusing to some

Note: The SPA504G has since been discontinued.

The OnSIP team is happy to see that Cisco is still pushing out new phones for their small business customers since taking Linksys under the Cisco brand. Their new Small Business Pro Series, which includes the SPA501G, 502G, 504G, 508G, and 509G, are the successors to the popular Linksys SPA9XX series. Although these new phones look very similar to the old Linksys series, there are actually a few noticeable upgrades that make them more than just a rebranding of the old models.

We thought we’d take a closer look at the phone in the middle of the pack: the SPA504G. The Cisco SPA504G is a midrange business desktop phone with an extensive feature list considering that you can pick one up for under $150. The phone supports 4 lines, each of which can be registered to separate SIP addresses. It also includes a high-resolution backlit LCD display, a full-duplex speakerphone, and a feature that’s particularly exciting to us—G.722 wideband audio support. Definitely not a bad start.

First Impressions

The Cisco 504G looks almost exactly the same as one of the Linksys phones we reviewed, the Linksys SPA 942. But upon closer inspection, we noticed the little differences. The number pad buttons are a lot closer together, the navigation pad is much more compact, and the handset is larger and lighter with a nice glossy sheen. The grey/silver over dark navy blue color scheme is exactly the same as that of the earlier Linksys models. Like the Linksys SPA 942, the 504G has colorful line display keys which change from green to red when a line goes active. The dedicated hard keys for mute, headset, and speakerphone also light up colorfully when they’re in use. The buttons depress very well but some of dedicated hard keys are not intuitively labeled. For example, “hold” is a palm and “setup” is a half turned page. Finally, an LED message-waiting indicator sits at the very top of the phone. Overall the phone looks and feels good. It is simple, but not in a bad way.

We were very excited when we heard that all of the phones in Cisco’s new Small Business Pro Series support wide band audio. It is encouraging to see another company developing HD voice capable phones that are not necessarily executive class phones or in the $200-300+ price range.

Phone Configuration

The Cisco 504G can be configured using the new Cisco Web Interface. Simply type the IP address of the phone (setup>network) into your web browser, and it will take you to the web UI. You’ll notice that you do not need any kind of login or password to get access to this. You also won’t need a password or login to get access to the admin options. We’re not sure if this is a good thing yet.

For an in-depth guide on registering a Cisco SPA504G with our OnSIP service, click here.

The Web UI itself allows for a lot of customizing. Many of the settings are up to you, and you might have to look through some of the pages to make sure that you have your phone set up the way you want it. For example, we had some minor issues getting DTMF transmission working properly just because we did not look through every page. Also, if you’re trying to set up separate lines, you’ll have to change the line appearances to correspond with the different SIP registrations, or else the phone will register all 4 lines under the first SIP registration. The Web UI may be a little confusing at first, and we’re hoping that they simplify it in the future.

When you save your settings, your phone will reboot for about 15-20 seconds. It’s also important to note that when you buy the Cisco 504G, it does not come with a power adapter—I’m guessing they’re assuming you’re going to use PoE. The Cisco PA100 Power Supply for Small Business VoIP is an accessory you have to purchase separately.

Junction Networks Interoperability Test

At Junction Networks, we put each of the phones we use through a multi-step interoperability test in which we put the phones through 30 test cases. An example of a test case would be the following:

“Test phone calls phone B

B picks up

B puts Test phone on hold

B calls phone C

C picks up

B transfers test phone to C

Call must be transferred correctly to C. B must be released correctly after the transfer. When C picks up, audio must work in both ways between test phone and C. When test phone is on hold, there is no audio between it and phone B.”

We are very happy to say that the Cisco 504G passed each test.

Voice Quality

If you set the preferred codec to G.722 in the web configuration interface, calls to other HD Voice compatible phones have fantastic call quality. The voice quality is comparable to what you get with some of the more expensive HD phones like the Polycom 550, which is definitely impressive. Unfortunately, you can only get the full benefits of a phone that supports wideband audio if the other end of the call is also using an HD voice compatible phone, and if the call is handled by IP from end to end. Calls to numbers using devices that do not support HD voice sound very good nonetheless.


The Cisco SPA504G includes a full duplex speakerphone that is an improvement over the one that came with the Linksys SPA492. Although you may have to play with the volume settings, this speakerphone is one of the better ones we’ve come across. Considering that it comes with a phone priced under $150 dollars, it is a very exciting high quality feature to have.

Ease of Use

We found the SPA504G very easy and intuitive to use. It has everything we need in a desk phone without getting overly complicated.

The backlit high-resolution display, although small, is very nice. All the context-sensitive options you need pop up just when you need them. For example, when you’re not on a call, you have options like “redial”, which takes you to a list of all your previous calls, “directory”, which holds hundreds of numbers, “call forwarding”, and “do not disturb”. During a call, the “soft” buttons change to “transfer” and “conference”. Other basic features you might need like “hold” and voicemail are saved for hard dedicated keys. The dedicated hard keys that correspond to mute, headset and speakerphone light up when pressed, letting you know the status of your call. You can also set different preferred volumes for your speakerphone, headset, and handset. One minor gripe we have with the phone is that the “setup” button leads to a list of 21 options, which is a lot considering only 4 of those options fit on the display screen at one time. You probably won’t have to navigate this setup menu very often, so this almost becomes a nonissue.

All of the features on the SPA504G work seamlessly together. The fact that the combination of hardware and software design contributes to such an intuitive user experience speaks for Cisco’s great understanding of their target customers.

Final Thoughts

The Cisco SPA504G is a very good phone. With HD voice supported, it delivers excellent voice quality in an intuitive and well-made piece of hardware. The OnSIP team is thrilled to see another manufacturer taking steps to bring HD voice to midrange phones that won’t cost customers an arm and a leg.

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