--- title: "Cisco 79XX - Troubleshoot MPLS/Circuit/ASA" slug: "cisco-79xx-troubleshoot-mpls-circuit-asa" tags: ["calltower", "public"] updated: 2026-09-18T13:42:53Z published: 2026-09-18T13:42:53Z canonical: "learn.calltower.com/cisco-79xx-troubleshoot-mpls-circuit-asa" --- > ## Documentation Index > Fetch the complete documentation index at: https://learn.calltower.com/llms.txt > Use this file to discover all available pages before exploring further. # Cisco 79XX - Troubleshoot MPLS/Circuit/ASA ## Goal To help the end-user troubleshoot the phone. This requires someone physically on-site to assist in the troubleshooting process. ## CASE DISPOSITION: - Case Record Type: Support Standard - Department: Support - Type: Problem - Product: Cisco - SubProduct: Hardware - Issue: 79xx - Sub Issue: Could be a few Sub Issues and will depend on the issue at hand. - Other Issue: N/A - Priority: (This will depend on how many phones are affected) - Severity: High - Urgency: Depends on how many phones are affected. ### Resolution/Steps 1. Confirm the phone has power, indicated by the phone screen lighting up/displaying information - If the customer's network provides power over Ethernet (PoE), the network cable should be firmly seated in the 10/100 SW port - If the customer's network doesn't provide PoE, there should be a power cable for an appropriate power supply firmly seated in the DC48V port 2. Confirm the model of the phone - This can be retrieved from Settings, Model Information (4), Model Number (1) - This may be able to be retrieved from the top right-hand corner of the phone screen frame - This may be able to be retrieved from the back of the phone, above the kickstand, on a sticker towards the top right, under the screw socket/hole 3. Confirm the MAC address of the phone - This can be retrieved from Settings, Model Information (4), MAC Address (2) - This may be able to be retrieved from the back of the phone, under the kickstand, from the MAC sticker section 4. Confirm the phone is built-in CallTower Connect - Now that you have the phone model and MAC, you can confirm the phone is showing built-in Connect - Go to the Phones section in CallTower Connect: - ![Connect Menu Phones.PNG](https://cdn.us.document360.io/4662144b-ab1f-4796-8b7b-e9f9c609894f/Images/Documentation/Connect_Menu_Phones(3).PNG?sv=2026-02-06&spr=https&st=2026-11-04T22%3A55%3A46Z&se=2026-11-04T23%3A55%3A46Z&sr=c&sp=r&sig=3nVS%2FSyPT3pGd4fxEnIc33e%2FFieJroNfp5do0aElYw8%3D) - Search the MAC to confirm it's built. - ![MAC Search.PNG](https://cdn.us.document360.io/4662144b-ab1f-4796-8b7b-e9f9c609894f/Images/Documentation/MAC_Search.PNG?sv=2026-02-06&spr=https&st=2026-11-04T22%3A55%3A46Z&se=2026-11-04T23%3A55%3A46Z&sr=c&sp=r&sig=3nVS%2FSyPT3pGd4fxEnIc33e%2FFieJroNfp5do0aElYw8%3D) 5. Confirm the phone is built-in Cisco Unified Communications Manager (Call Manager/CUCM) - Now that you have the phone model and MAC, you can confirm the phone is showing built-in CUCM - You will need to know what Call Manager Cluster the customer is built on. - In CallTower Connect on the "Customers" page you can expand the page and under "Customer Details" it has the cluster under "CM Resource" - "Customers" Menu:![Connect Menu Customers.PNG](https://cdn.us.document360.io/4662144b-ab1f-4796-8b7b-e9f9c609894f/Images/Documentation/Connect_Menu_Customers.PNG?sv=2026-02-06&spr=https&st=2026-11-04T22%3A55%3A46Z&se=2026-11-04T23%3A55%3A46Z&sr=c&sp=r&sig=3nVS%2FSyPT3pGd4fxEnIc33e%2FFieJroNfp5do0aElYw8%3D) - "Customer Details" and "CM Resource" - ![Connect Cluster.PNG](https://cdn.us.document360.io/4662144b-ab1f-4796-8b7b-e9f9c609894f/Images/Documentation/Connect_Cluster.PNG?sv=2026-02-06&spr=https&st=2026-11-04T22%3A55%3A46Z&se=2026-11-04T23%3A55%3A46Z&sr=c&sp=r&sig=3nVS%2FSyPT3pGd4fxEnIc33e%2FFieJroNfp5do0aElYw8%3D) 6. Confirm the phone is connecting to the network - The IP Address can be retrieved from Settings, Network (3), IP Address (6) #### Intermediate troubleshooting (by symptom) **Network connection unavailable/Configuring IP** 1. Review the IP address of the phone, Basic troubleshooting step 6 - Phone should have a 10.252.X.X (Customer managed LAN), 10.253.X.X (Sprint MPLS), 10.254.X.X (CallTower MPLS) IP address - The phone should have a 192.168.22.X (ASA) IP address - IP's listed are "default", a customer could have custom IP range, review account SHN - If the phone has any other IP, it is most likely connected to the wrong network 2. Erase the Network Configuration - Settings, highlight Network Configuration, more, Erase - If Erase is "gray", use **# to unlock the settings 3. Review the IP address of the phone - The phone should now be getting a valid IP if connected to the right LAN, this portion of troubleshooting is complete - If the phone is displaying 0.0.0.0, proceed to the next appropriate step 4. Confirm cabling - Confirm network cable is firmly seated in the 10/100 SW port on the phone, and the other end into the customers LAN - The phone should grab an IP within 2-3 minutes, see step 3 5. Rule out the network cable - Use another/known working network cable if available, see step 4 6. Rule out network port - Move the phone to a known working network port where an existing phone is currently registered, see step 4 7. Rule out network topology (network equipment/patch panel/cable run) - Connect the phone directly to the DHCP server if possible, see step 4 8. At this point, if the phone is still failing to get an IP address, it will need to be reviewed by a Tier 2 or Tier 3. **Registering/Registration rejected** 1. Confirm the correct model/MAC is built-in Connect and CUCM - See Basic troubleshooting steps 2 and 3 - If incorrect, rebuild the phone with the correct model/MAC, otherwise, proceed to step 2 2. Review Alternate TFTP settings - Navigate to Settings, Network Configuration (3), Alternate TFTP (32), Should be set to NO - Use **# to unlock the settings and update to NO if needed - If Alternate TFTP is currently set to NO or was updated to NO, and the phone is still failing to register, proceed to step 3 - Phones should not need to have TFTP set to YES, DHCP opt 150 should be configured on the ASA/router to provide the correct CUCM cluster 3. Clear the ITL/CTL file(s) - Navigate to Settings, Security Configuration (6), highlight ITL/CTL - If either the ITL/CTL file are listed with anything other than "Not Installed", erase the entries - Use **# to unlock the settings if needed - Erasing the ITL or CTL file will clear both if present, and should reboot the phone 4. At this point, if the phone is still failing to register, it will need to be reviewed by T2+ #### Phone stuck in a boot loop 1. Confirm the correct model/MAC is built-in Connect and CUCM - See Basic troubleshooting steps 2 and 3 2. Factory reset the phone - See attached document Factory Reset 7900 Series IP Phones for Cisco documentation on this process 3. At this point, if the phone is still stuck in a boot loop, it will need to be reviewed by T2+ ## Additional Information **What's next?** If there are any symptoms outside of the scope of this document, or any items that need clarification, please reach out/escalate to a Tier 2. ## Common Issues/Related Articles Factory Reset: - 7940 and 7960: [{{ glossary.UC}}.solutions/Cisco/002Phones/79XX_Series/Cisco_-_Phone%3A_7940_and_7960_Factory_Reset_Procedure">Cisco - Phone: 7940 and 7960 Factory Reset Procedure](/v1/docs/cisco-79xx-7940-and-7960-factory-reset-procedure) - 7920: [Cisco - Phone: 7920 Factory Reset Procedure](/v1/docs/cisco-79xx-factory-reset-procedure) - 7942 and 7962: Cisco - Phone: 7942 and 7962 Factory Reset Procedure - 7945, 7965, and 7975: [Cisco - Phone: 7945, 7965, 7975 Factory Reset Procedure](/v1/docs/cisco-79xx-7945-7965-7975-factory-reset-procedure) - 7921: [Cisco - Phone: 7921 Factory Reset Procedure](/v1/docs/cisco-79xx-7921-factory-reset-procedure) - 7925: [Cisco - Phone: 7925 Factory Reset Procedure](/v1/docs/cisco-79xx-7925-factory-reset-procedure) 79XX Features: - [Cisco - Phone: Overview - 79XX Series](/v1/docs/cisco-79xx-series-overview) - [Cisco - Phone: iDivert - 79XX Series](/v1/docs/cisco-79xx-idivert) - [Cisco - Phone: Pickup - 79XX Series](/v1/docs/cisco-79xx-call-pickup) - [Cisco - Phone: Extension Mobility - 79XX Series](/v1/docs/cisco-79xx-extension-mobility) - [Cisco - Phone: Joining Calls - 79XX Series](/v1/docs/cisco-79xx-joining-calls) - [Cisco - Phone: Receiving Calls - 79XX Series](/v1/docs/cisco-79xx-receiving-calls) - [Cisco - Phone: Call Park - 79XX Series](/v1/docs/cisco-79xx-call-park) - [Cisco - Phone: Speed Dials - 79XX Series](/v1/docs/cisco-79xx-speed-dials) - [Cisco - Phone: Transferring a Call - 79XX Series](/v1/docs/cisco-79xx-transferring-a-call) - [Cisco - Phone: Do Not Disturb (DND) - 79XX Series](/v1/docs/cisco-79xx-do-not-disturb) - [Cisco - Phone: Answering Additional Calls - 79XX Series](/v1/docs/cisco-79xx-answering-additional-calls) - [Cisco - Phone: Cisco Function Directories - 79XX Series](/v1/docs/cisco-79xx-function-directories) - [Cisco - Phone: Switching Between Calls - 79XX Series](/v1/docs/cisco-79xx-switching-between-calls) - [Cisco - Phone: Cisco Function Settings - 79XX Series](/v1/docs/cisco-79xx-function-settings) - [Cisco - Phone: Cisco Function Buttons - 79XX Series](/v1/docs/cisco-79xx-function-buttons) - [Cisco - Phone: Returning to Initial Call - 79XX Series](/v1/docs/cisco-79xx-returning-to-initial-call) - [Cisco - Phone: Placing a Call on Hold - 79XX Series](/v1/docs/cisco-79xx-placing-a-call-on-hold) - [Cisco - Phone: Call Forwarding an Incoming Call - 79XX Series](/v1/docs/cisco-79xx-call-forwarding-an-incoming-call) - [Cisco - Phone: Meet Me Conference Call - 79XX Series](/v1/docs/cisco-79xx-meet-me-conference-call) - [Cisco - Phone: Cisco Call Forwarding All - 79XX Series](/v1/docs/cisco-79xx-call-forwarding) - [Cisco - Phone: Placing a Call - Internal, External, 911 or 411 - 79XX Series](/v1/docs/cisco-79xx-placing-a-call) CallTower Connect is is CallTower’s online management portal that lets administrators easily manage users, phone numbers, services, reporting, and communication settings all in one place. An Internet Protocol (IP) Address is a unique string of numbers separated by periods that identifies each computer using the Internet Protocol to communicate over a network.