Plain old telephone service (POTS) functionality refers to the use of the voice capabilities of the ISDN routers. The ringer equivalent number (REN) consists of a number and a letter that indicates the frequency response of that telephone's ringer. The term telephone port refers to the physical port on the router back panel. The telephone interface refers to a logical interface that you have to configure to make an analog telephone, fax, or modem connected to the router port (phone 1 and 2) work properly as touch-tone devices. The set of configuration commands related to the configuration of the physical ports includes the country, resistance of the line, dialing method, disconnect supervision, encoding, and ringing frequency. Most of the default settings are for the U.S. The first thing to check in the global configuration mode of the router is who is providing the tones and how the following command is set up: 804-isdn(config)# pots tone-source {local | remote} This command sets who supplies dial, ring back, and busy tones for telephones, fax machines, or modems connected to a Cisco IOS-based ISDN router. The keywords are as follows:
Specifically for supplying the dial tone, another global configuration command is available with same local and remote options: 804-isdn(config)#pots dial-tone {local | remote} In the global configuration command, another command specifies the delay after which a telephone port can be rung after a previous call is disconnected: 804-isdn(config)#pots distinctive-ring-guard-time milliseconds The milliseconds argument is the number of milliseconds of the delay and ranges from 0 to 1000. The default depends on the chosen country. You can connect multiple devices (analog telephones, fax machines, and modems) to a router telephone port. The number you can connect depends on the REN of the telephone port (five) or the REN of each device that you plan to connect. If you have five devices and all of them have REN 1, you can connect all of them to the POTS port. Creating Dial PeersDial peers determine the routing of incoming calls to the telephone ports. You can create a total of six dial peers for the two telephone ports. Example 11-9 lists some of the relevant Cisco IOS Software configuration commands. Example 11-9. A Common Procedure for Dial Peers Configuration! This command sets up a tag number (1 to 6): 804-isdn(config)#dial-peer voice tag pots ! This command assigns a local directory number: 804-isdn(config-dial-pe)#destination-pattern ldn ! The number of the port is defined using the following command: 804-isdn(config-dial-pe)#port port-number ! The following command disables call waiting (optional): 804-isdn(config-dial-pe)#no call-waiting ! This command (optional) sets a custom ring. Any call coming to that port will ! use that ring. The cadence-number can be 0,1, or 2: 804-isdn(config-dial-pe)#ring cadence-number The configuration is displayed if you type show dial-peer voice 5, as shown in Example 11-10. Example 11-10. Displaying the Configuration of dialer-peer 5 804-isdn#show dial-peer voice 5 VoiceEncapPeer5 tag = 5 destination-pattern = '3335555' voice-port = 2 ring cadence = 0 call-waiting disabled forward_to_unused_port disabled The local directory number (LDN) must be associated with a service profile identifier (SPID). If you do not assign LDN to both SPIDs, you cannot make voice calls simultaneously. If the dial peers are not created, all voice calls are routed to port 1. To ensure you allow incoming and outgoing voice calls under a BRI interface, configure the following command: 804-isdn(config-if)#isdn incoming-voice modem The simple configurations enable the basic POTS functionality of the voice portion of ISDN service. There are some advanced features, and their number is continuously changing and growing. Some of them are discussed in the next paragraph. Advanced Telephone FeaturesThis section provides coverage of some of the more advanced features provided by Cisco IOS Software-based ISND configuration, including the following:
ISDN Voice PriorityThe voice priority feature of IOS handles the data and voice priority. Depending on the user preferences, voice could take precedence over data and vice versa. There are three options:
In Cisco 700 series routers, a set of commands handles the process, as displayed in Example 11-11. Example 11-11. Voice Priority Settings for 77x Router776-isdn>SET VOICEPRIORITY INCOMING INTERFACE PHONE1 CONDITIONAL 776-isdn>SET VOICEPRIORITY OUTGOING INTERFACE PHONE1 CONDITIONAL 776-isdn>SET CALLWAITING INTERFACE PHONE1 ON 776-isdn>SET VOICEPRIORITY INCOMING INTERFACE PHONE2 ALWAYS 776-isdn>SET VOICEPRIORITY OUTGOING INTERFACE PHONE2 ALWAYS 776-isdn>SET CALLWAITING INTERFACE PHONE2 ON 776-isdn>SET CALLTIME VOICE INCOMING OFF 776-isdn>SET CALLTIME VOICE OUTGOING OFF 776-isdn>SET CALLTIME DATA INCOMING OFF 776-isdn>SET CALLTIME DATA OUTGOING OFF The result of this configuration for a Cisco 700 series router is displayed in Example 11-12. Example 11-12. Verifying Voice Priority Settings on the 776 Router 776-isdn>show voice Interface VoicePriority VoicePriority Call Directory Ring In Out Waiting Number Cadence PHONE1 CONDITIONAL CONDITIONAL ON 5764740 PHONE2 ALWAYS ALWAYS ON 5764741 DOV N/A N/A N/A UNSPECIFIED N/A N/A N/A For IOS-based routers, the commands are 804-isdn#isdn voice-priority ldn {in | out}{always | conditional | off} The pots dialing-method {overlap | enblock} command affects the way you receive a busy signal. With the overlap option, you hear a fast busy signal. With enblock, you initially hear a dial tone followed by a busy signal. If you cannot make the configuration settings work correctly, it's possible that the LEC is blocking voice calls, the line was provisioned without additional call offering (ACO), or the router is rejecting voice calls due to an incorrect configuration. Supplementary Phone ServicesCisco supports some supplementary phone services that are available in Cisco IOS Software. Use of these services is possible, but not mandatory; it depends on the way the line is provisioned. Some of the phone services might include the following, depending on the LEC settings:
|