MCM Field Notes · Updated weekly

MCM Field Notes

Operator-grade insights on cloud telephony, AI receptionists, wholesale routing, and contact-center operations — written by the engineers and ops teams who actually run MCM.

// Welcome

Welcome to MCM Field Notes

The newest field report sits at the top — long-form operator notes on cloud telephony, AI receptionists, and the wholesale routing decisions behind them.

What is wholesale VoIP termination: your platform, a wholesale carrier and the destination network, billed per minute
Updated Oct 14, 2026Wholesale VoIP

Wholesale VoIP Termination: The Carrier Guide

Wholesale VoIP termination explained — SIP call flow, ASR/ACD/PDD quality metrics, codec stack, Premium/Standard/Call Center routes, STIR/SHAKEN compliance, fraud patterns, and how to evaluate any carrier.

Continue reading

// The archive

More from the field

36 posts

917 area code — NYC's first overlay and original mobile prefix, born February 4 1992, covers all five boroughs

Area Code

917 Area Code: NYC's First Mobile Number

The 917 area code is New York City's first mobile-first prefix. See why it carries city-wide credibility and how to get a 917 number.

Updated Sep 28, 2026Read
305 area code covering Miami and the Florida Keys

Area Code

305 Area Code: Miami Map, Overlays & Numbers

The 305 area code covers Miami and the Florida Keys. See cities, counties, time zone, the 786 and 645 overlays, and how to get a number.

Updated Aug 28, 2026Read
Map of West Virginia marking Charleston, Huntington and Morgantown with a 304 badge

Area Code

304 Area Code: West Virginia Cities, Map & 681 Overlay

The 304 area code covers all of West Virginia, Charleston to Wheeling. Learn its 681 overlay, time zone, dialing rules, scams, and how to get a 304 number.

Updated Aug 24, 2026Read
218 area code infographic showing Duluth's Aerial Lift Bridge and an ore boat on Lake Superior with a stylised map of northern Minnesota and a 218 badge

Area Code

218 Area Code: Duluth & Northern Minnesota Guide

The 218 area code covers all of northern Minnesota — Duluth, the Iron Range, Bemidji, Brainerd. See its regions, dialing, and how to get a 218 number.

Updated Aug 24, 2026Read
California map showing the 760 area code across coast, desert, and Sierra regions

Area Code

760 Area Code: California Coverage & City Map

The 760 area code spans north San Diego County and California's deserts. Explore its cities, counties, 442 overlay, and how to get a local number.

Updated Aug 24, 2026Read
614 area code infographic for Columbus, Ohio

Area Code

614 Area Code: Numbers in Columbus, Ohio

The 614 area code covers Columbus and central Ohio. Get its cities, counties, the 380 overlay, time zone, and how to claim a local number.

Updated Aug 24, 2026Read
414 area code infographic for Milwaukee, Wisconsin — one code since 1947, Central Time

Area Code

414 Area Code: How Milwaukee Keeps One Code

The 414 area code is Milwaukee's original 1947 code — and still its only one. See cities, counties, dialing rules, time zone, and how to get a number.

Updated Aug 24, 2026Read
559 area code infographic showing Fresno and the Central Valley region of California

Area Code

559 Area Code: Dialing & the 357 Overlay

The 559 area code covers Fresno and Central Valley California. See cities, the 357 overlay, dialing rules, and how to get a 559 number.

Updated Aug 24, 2026Read
313 area code badge over the Detroit, Michigan skyline

Area Code

313 Area Code: Detroit's Code Plus New 679

The 313 area code covers Detroit, Michigan. See its cities, time zone, the new 679 overlay, 10-digit dialing rules, and how to get a 313 number in 2026.

Updated Aug 24, 2026Read
661 area code — Bakersfield, Kern County, and northern LA County valleys, Pacific Time, split from 805 in 1999

Area Code

661 Area Code: Map, Scams & Getting a Number

The 661 area code covers Bakersfield, Santa Clarita and Kern County. Here are its cities, time zone, scam risks, and how to get a 661 number.

Updated Aug 24, 2026Read
210 area code — San Antonio location, cities, and the 726 overlay

Area Code

210 Area Code: San Antonio Cities & 726 Overlay

Everything about the 210 area code in San Antonio, Texas: counties served, the 726 overlay, time zone, dialing rules, and getting a local number.

Updated Aug 24, 2026Read
916 Area Code · Sacramento Cities, Dialing and Numbers — feature hero with the post title prominent on the left, a description line about the state-capital prefix covering 6 counties and paired with the 279 overlay since 2018, plus a row of key city chips for Sacramento Roseville Elk Grove Folsom Davis Auburn Citrus Heights and Rocklin and a facts strip showing Since 1947, 6 counties, 279 overlay, and 10-digit dialing; right side shows the California state-capitol dome silhouette over a +1 (916) 555-0123 dial format line, plus a compact incoming-call phone tile

Area Code

916 Area Code: Sacramento Numbers & Dialing

The 916 area code covers Sacramento and five counties. Get the cities, 279 overlay facts, dialing rules, and how to claim a local number.

Updated Aug 24, 2026Read
678 area code — metro Atlanta full-coverage overlay since 1998, sits with 404, 770, 470, and 943 across the same map, Eastern Time

Area Code

678 Area Code: The Metro Atlanta Overlay

The 678 area code is a metro Atlanta overlay. Learn the cities it covers, its time zone, how it relates to 404/770/470/943, and how to get one.

Updated Aug 24, 2026Read
813 area code overview card for Tampa and Hillsborough County, Florida, with a Tampa skyline and county map

Area Code

813 Area Code: Tampa Numbers & the 656 Overlay

The 813 area code covers Tampa and Hillsborough County, Florida. See its cities, the 656 overlay, dialing rules, and how to get an 813 number.

Updated Aug 24, 2026Read
562 area code — Long Beach and southeast LA County, split from 310 in January 1997, still single-code today with no overlay, Pacific Time

Area Code

562 Area Code: Long Beach Coverage & Numbers

The 562 area code covers Long Beach and southeast LA. Learn its cities, Pacific time zone, scam risks, and how to get a local 562 number fast.

Updated Aug 24, 2026Read
727 area code overview infographic showing St. Petersburg and Pinellas County, Florida on the Gulf Coast

Area Code

727 Area Code: Florida Cities, Map & Coverage

The 727 area code covers Pinellas County and St. Petersburg, FL. See its cities, time zone, dialing rules, and how to get a local number.

Updated Aug 22, 2026Read
904 area code infographic with Jacksonville skyline and Florida map labeled The First Coast

Area Code

904 Area Code: Counties, Cities & 324 Overlay

The 904 area code covers Jacksonville and Northeast Florida. Get the cities, counties, time zone, the new 324 overlay, and 10-digit dialing rules.

Updated Aug 22, 2026Read
805 area code hero graphic for California's Central Coast with a smartphone showing an incoming Santa Barbara call

Area Code

805 Area Code: Local Numbers & Dialing Rules

Where is the 805 area code? Cities, counties, the 820 overlay, time zone, dialing rules, and how to get an 805 number for your business.

Updated Aug 21, 2026Read
Map of Central New York with Syracuse pinned and a 680 area code badge beside the 315 overlay label

Area Code

680 Area Code: Syracuse & Central New York Coverage

Area code 680 overlays 315 across Syracuse, Utica, and Central New York, in service since March 11, 2017. See exactly which counties it reaches and how to dial.

Updated Aug 20, 2026Read
615 area code — incoming call from Nashville, TN, marked LOCAL across Middle Tennessee

Area Code

615 Area Code: Nashville Map & Dialing Tips

The 615 area code covers Nashville and Middle Tennessee. See which cities and counties it serves, the 629 overlay, dialing rules, and how to get a number.

Updated Aug 20, 2026Read
The 202 Area Code — The Washington D.C. Guide for 2026. Everything you need to know about the 202 area code, overlay, dialing rules, and why a D.C. number builds real credibility. US map with Washington D.C. highlighted in violet. DC diamond outline. Phone Number Format breakdown: +1 + 202 + 555-1234. Feature pills: What the 202 Area Code Covers, 771 Overlay, 10-Digit Dialing Rules, Why a D.C. Number Builds Trust.

Area Code

202 Area Code: Capitol Hill, Georgetown, and Adams Morgan Guide

Everything about Washington D.C.'s 202 area code — the District quadrants and neighborhoods it covers, the 771 overlay, Eastern time zone, and how to get a local DC number in 2026.

Updated Aug 19, 2026Read
317 area code infographic for Indianapolis, Indiana

Area Code

317 Area Code: Dialing, Map & Indianapolis Cities

The 317 area code covers Indianapolis and 9 central Indiana counties. Get the cities, time zone, 463 overlay rules, and how to claim a 317 number.

Updated Aug 19, 2026Read
215 area code infographic for Philadelphia, PA showing a coverage map and the city skyline

Area Code

215 Area Code: Numbers & Coverage in Philadelphia

What the 215 area code covers, who it serves, overlay codes 267 and 445, and how to get a Philadelphia number. Verified 2026 guide.

Updated Aug 18, 2026Read
The 518 Area Code — Your Guide to Albany & Upstate New York. Map of New York with the Capital Region highlighted green at Albany. Covers the Capital Region and surrounding upstate New York counties. Time Zone Eastern Time ET. 838 Overlay. In service since 1947 as one of New York's original area codes. Get a local 518 number to show your business belongs in the Capital Region and Upstate New York.

Area Code

518 Area Code: Albany & Upstate New York

Everything about New York's 518 area code — the Capital Region and upstate cities it covers (Albany, Schenectady, Troy, Saratoga Springs, Plattsburgh), the 838 overlay, Eastern time zone, and how to get a local Albany number in 2026.

Updated Aug 18, 2026Read
Greetings from 609 New Jersey — vintage postcard hero for the 609 area code, covering Trenton, Atlantic City, Princeton, Cape May, and central and southern New Jersey since 1957, paired with the 640 overlay in 2018, all on Eastern Time

Area Code

609 Area Code: New Jersey Cities & Number Map

Where is the 609 area code? Covers Trenton, Atlantic City and central-south NJ. See cities, counties, the 640 overlay, and how to get a number.

Updated Aug 18, 2026Read
864 Area Code Upstate South Carolina guide showing Greenville on a map with 821 overlay, Eastern Time, and 10-digit dialing

Area Code

864 Area Code: Numbers in Upstate South Carolina

The 864 area code covers Greenville and upstate South Carolina. See its cities, counties, time zone, and the new 821 overlay in this 2026 guide.

Updated Aug 18, 2026Read
816 area code infographic for Kansas City, Missouri, with the city skyline and regional coverage map

Area Code

816 Area Code: Kansas City Numbers & Coverage

Where the 816 area code reaches, the new 975 overlay, time zone facts, and how to get a Kansas City number. Verified for 2026.

Updated Aug 18, 2026Read
501 area code — central Arkansas cities, Little Rock, and how to get a number

Area Code

501 Area Code: Numbers for Central Arkansas

A complete guide to the 501 area code in central Arkansas: cities served, time zone, dialing rules, and how to get a 501 number for your business.

Updated Aug 18, 2026Read
972 area code — Dallas metro guide

Area Code

972 Area Code: Numbers Across the Dallas Metro

The 972 area code covers Dallas and its eastern suburbs. See cities, counties, the four-code overlay, time zone, and how a 972 number helps.

Updated Aug 18, 2026Read
657 area code — Orange County coverage

Area Code

657 Area Code: Numbers for Orange County

The 657 area code overlays 714 in Orange County, CA. Learn its cities, dialing rules, and how to get a 657 number for your business.

Updated Aug 18, 2026Read
913 area code — Kansas City KS cities, counties, and dialing

Area Code

913 Area Code: Kansas City KS Counties & Dialing

The 913 area code covers Kansas City KS, Overland Park and 10 counties. See its cities, time zone, 7-digit dialing rule, and how to get a number.

Updated Aug 18, 2026Read
The 717 Area Code — South-Central Pennsylvania Phone Guide. Area Code Guide 2026. Harrisburg, Lancaster, York. Covers Harrisburg, Lancaster and York. 223 overlay. 10-digit dialing. Eastern Time. Pennsylvania state outline showing three pin markers at Harrisburg, Lancaster, and York. Local presence for South-Central PA businesses.

Area Code

717 Area Code: Phones Across South-Central PA

Everything about Pennsylvania's 717 area code — the south-central PA cities it covers (Harrisburg, Lancaster, York), the 223 overlay, Eastern time zone, and how to get a local number in 2026.

Updated Aug 18, 2026Read
The 714 Area Code — Orange County Phone Guide 2026. Anaheim, Santa Ana, Huntington Beach, Fullerton, Garden Grove, Costa Mesa. Pacific Time. 657 overlay since 2008. 10-digit dialing required.

Area Code

714 Area Code: Orange County Local Numbers

Everything about the 714 area code: cities, counties, the 657 overlay, dialing rules, and how to get a local Orange County number in 2026.

Updated Aug 18, 2026Read
530 area code map of northern California covering Redding, Chico, and Lake Tahoe with the new 837 overlay note

Area Code

530 Area Code: Redding, Chico & Northern Calif.

The 530 area code covers Redding, Chico, and northeastern California. See the cities, counties, the new 837 overlay, and how to get a number.

Updated Aug 18, 2026Read
The 205 Area Code — The Complete Birmingham, Alabama Guide. Vintage Alabama state outline with Birmingham skyline illustration and a navy + crimson '205 AREA CODE' ticket badge. Where the 205 Area Code Covers · Time Zone Central Time CT · 659 Overlay · How to Get a 205 Number for your business in Alabama.

Area Code

205 Area Code: Everything on Birmingham, Alabama

Everything about Alabama's 205 area code — the central and west AL cities it covers (Birmingham, Tuscaloosa, Hoover), the 659 overlay, Central time zone, and how to get a local Birmingham number in 2026.

Updated Aug 18, 2026Read
757 area code map of Hampton Roads, Virginia, showing the Virginia Peninsula and South Hampton Roads

Area Code

757 Area Code: Dialing in Hampton Roads, VA

Where is the 757 area code? Hampton Roads cities, counties, the 948 overlay, time zone, dialing rules, and how to get a 757 number.

Updated Aug 17, 2026Read

// The rest

Every field note

459 posts

MCM Field Notes · Monthly

One email a month. 8,400 ops leaders read it.

Field reports on cloud telephony, AI receptionists, wholesale routing — written by the engineers who run the network. No fluff, no thought leadership.

No spam. Unsubscribe in one click.

// Follow MCM

Get fresh field reports the moment they ship.

LinkedInFacebookXYouTube
FAQ

Questions about the MCM blog.

Weekly. Field reports drop most Tuesdays — written by the engineers and ops teams who actually run the network, not freelancers.

Featured research

Explore more on the platform

/blog/

UCaaS vs CCaaS in 2026

When the two collapse into one bill — and what to look for in the platform that gets you there.

Read more
/blog/

Replacing RingCentral: a 14-day playbook

Port numbers, retire SBCs, retrain agents — without dropping a call.

Read more
/blog/

AI receptionist cost-per-call benchmarks

Industry benchmarks for AI-handled minutes versus human-only baselines.

Read more

Try the platform. Be on a call by lunch.

Same product, same support, same security — no matter which plan you pick.

Start a TrialBook a Demo