How to write search filter for searching a mobile number or telephone number in LDAP?

I want to query LDAP using search filters. For connecting to the LDAP server I am using node.js.

I am able to search any name in LDAP using the search filter. But when I try to search for any mobile number or telephone number i am getting the error: request timeout (client interrupt).

Here is the node.js code that works when I search for a name:

var ldap = require('ldapjs');
var sys   = require('sys');
var assert   = require('assert-plus');

var username = 'XXXXXXX';
var password = 'XXXXXXX';
var domain = "cts.com";
var searchBase = 'dc=cts,dc=com';


var client = ldap.createClient({
    url: 'ldap://myipaddress:portnumber',
    bindDN: "cts.com",
    timeout: 5000,
    connectTimeout: 10000
});

client.bind('cts\\'+username, password, function (err) {
    if (err) {
        console.log(err);
        client.unbind(function (err) {
            console.log('3');
            if (!err) {
                console.log('successfully unbind');
            }
            else {
                console.log(err);
            }
        });
    } else {
        console.log('authenticated');
        var searchResult = search();
    }
});

function search(){
    var opts = {
        filter:'(sAMAccountName='+username+')',
        scope: 'sub',
        attributes: ['sAMAccountName','name','givenName','distinguishedName','displayName','cn','sn',
                    'mail','title','description','department','company','manager',
                    'telephoneNumber','mobile','co','c','l','st','postalCode'],
    };

    client.search(searchBase, opts, function(err, res) {
        assert.ifError(err);

        res.on('searchEntry', function(entry) {
            console.log('searchEntry');
            var user = entry.object;
            console.log(user.objectGUID);
            if(entry.object){
                console.log('entry: %j ' + JSON.stringify(entry.object))
            }
        });
        res.on('searchReference', function(referral) {
            console.log('searchReference');
            console.log('referral: ' + referral.uris.join());
        });
        res.on('error', function(err) {
            console.error('error: ' + err.message);
        });
        res.on('end', function(result) {
            console.log('status: ' + result.status);
            return result;      
        });
    });
}

The result I get after running the above code in command prompt is:

authenticated
undefined
searchEntry
undefined

entry: %j {"dn":"CN=anyname,OU=Users,OU=DLF,OU=Chennai,OU=India,OU=APAC,OU=mycompanyname,DC=cts,DC=com","controls":[],"cn":"name","sn":"K-5","c":"IN","l":"C
    hennai","st":"TN","title":"Developer","description":"Associate","postalCode":"600089","telephoneNumber":"123455","givenName":"XXXXXXXXX","distinguis
    hedName":"CN=XXXXXXXX,OU=Users,OU=DLF,OU=Chennai,OU=India,OU=APAC,OU=Cognizant,DC=cts,DC=com","displayName":"XXXXXXXX","co":"IND","department":"Mobility-MM","company":"Any Company Name","name":"anyname","sAMAccountName":"employeeID","mail":"mailid@gmail.com","mobile":"999-091-3918"
}

Next I need to search LDAP for the field "mobile". So what i did was, i rewrite the search filter as

var searchNumber = '999-091-3918';

var opts = {
        filter:'(mobile='+searchNumber+')',
        scope: 'sub',
        attributes: ['sAMAccountName','name','givenName','distinguishedName','displayName','cn','sn',
                    'mail','title','description','department','company','manager',
                    'telephoneNumber','mobile','co','c','l','st','postalCode'],
    };

and run the code.

This time i get error request timeout (client interrupt). Can anyone help me how to write search filter for mobile and telephone number in LDAP?